Knowledge

Adjoint functors

Source πŸ“

3520: 2842: 16484: 11819: 5160: 11325: 11308: 16731: 16751: 16741: 4273: 15128: 11814:{\displaystyle {\begin{aligned}f=\Phi _{Y,X}^{-1}(g)&=\varepsilon _{X}\circ F(g)&\in &\,\,\mathrm {hom} _{C}(F(Y),X)\\g=\Phi _{Y,X}(f)&=G(f)\circ \eta _{Y}&\in &\,\,\mathrm {hom} _{D}(Y,G(X))\\\Phi _{GX,X}^{-1}(1_{GX})&=\varepsilon _{X}&\in &\,\,\mathrm {hom} _{C}(FG(X),X)\\\Phi _{Y,FY}(1_{FY})&=\eta _{Y}&\in &\,\,\mathrm {hom} _{D}(Y,GF(Y))\\\end{aligned}}} 7356:, by formally adding an additive inverse for each bundle (or equivalence class). Alternatively one can observe that the functor that for each group takes the underlying monoid (ignoring inverses) has a left adjoint. This is a once-for-all construction, in line with the third section discussion above. That is, one can imitate the construction of 13292: 13074: 6454:. Any limit functor is right adjoint to a corresponding diagonal functor (provided the category has the type of limits in question), and the counit of the adjunction provides the defining maps from the limit object (i.e. from the diagonal functor on the limit, in the functor category). Below are some specific examples. 14729: 2303:
The equivalency of these definitions is quite useful. Adjoint functors arise everywhere, in all areas of mathematics. Since the structure in any of these definitions gives rise to the structures in the others, switching between them makes implicit use of many details that would otherwise have to be
1842:
Common mathematical constructions are very often adjoint functors. Consequently, general theorems about left/right adjoint functors encode the details of many useful and otherwise non-trivial results. Such general theorems include the equivalence of the various definitions of adjoint functors, the
12614:
A similar argument allows one to construct a hom-set adjunction from the terminal morphisms to a left adjoint functor. (The construction that starts with a right adjoint is slightly more common, since the right adjoint in many adjoint pairs is a trivially defined inclusion or forgetful functor.)
4161:
This definition is a logical compromise in that it is more difficult to satisfy than the universal morphism definitions, and has fewer immediate implications than the counit–unit definition. It is useful because of its obvious symmetry, and as a stepping-stone between the other definitions.
3841:
These definitions via universal morphisms are often useful for establishing that a given functor is left or right adjoint, because they are minimalistic in their requirements. They are also intuitively meaningful in that finding a universal morphism is like solving an optimization problem.
14929: 11966: 5032: 13990: 12858: 4494: 4871: 6786:. Any colimit functor is left adjoint to a corresponding diagonal functor (provided the category has the type of colimits in question), and the unit of the adjunction provides the defining maps into the colimit object. Below are some specific examples. 13120: 12902: 1190: 15381: 5819:
is fully determined by its action on generators, another restatement of the universal property of free groups. One can verify directly that this correspondence is a natural transformation, which means it is a hom-set adjunction for the pair
6300: 6029: 9374: 6757:
A suitable variation of this example also shows that the kernel functors for vector spaces and for modules are right adjoints. Analogously, one can show that the cokernel functors for abelian groups, vector spaces and modules are left
404: 13520: 8558:, quantifiers are identified with adjoints to the pullback functor. Such a realization can be seen in analogy to the discussion of propositional logic using set theory but the general definition make for a richer range of logics. 2288:
The definitions via universal morphisms are easy to state, and require minimal verifications when constructing an adjoint functor or proving two functors are adjoint. They are also the most analogous to our intuition involving
15473:
However, universal constructions are more general than adjoint functors: a universal construction is like an optimization problem; it gives rise to an adjoint pair if and only if this problem has a solution for every object of
14610: 4645: 4578: 597: 524: 10082: 4114: 10294: 15123:{\displaystyle {\begin{aligned}&1_{\mathcal {E}}{\xrightarrow {\eta '}}G'F'{\xrightarrow {G'\eta F'}}G'GFF'\\&FF'G'G{\xrightarrow {F\varepsilon 'G}}FG{\xrightarrow {\varepsilon }}1_{\mathcal {C}}.\end{aligned}}} 13713: 10178: 8390: 6744:, which expresses the universal property of kernels. The counit of this adjunction is the defining embedding of a homomorphism's kernel into the homomorphism's domain, and the unit is the morphism identifying a group 3996: 9447: 11832: 4898: 2974: 773: 707: 8676: 3652: 14228: 14127: 8200: 210: 170: 1816: 13852: 1045:, and indeed every equivalence is an adjunction. In many situations, an adjunction can be "upgraded" to an equivalence, by a suitable natural modification of the involved categories and functors. 10959: 14934: 14615: 13857: 13793: 13600: 13125: 12907: 12733: 11837: 11330: 4903: 4788: 4413: 1335: 15691: 12728: 9568: 10868: 4408: 3519: 6197: 5927: 4783: 13394: 5876: 4735: 2387:). If the arrows for the left adjoint functor F were drawn they would be pointing to the left; if the arrows for the right adjoint functor G were drawn they would be pointing to the right. 14858: 1667: 1610: 10914: 6581:
etc. follow the same pattern; it can also be extended in a straightforward manner to more than just two factors. More generally, any type of limit is right adjoint to a diagonal functor.
15746: 10987: 2659: 58:. Pairs of adjoint functors are ubiquitous in mathematics and often arise from constructions of "optimal solutions" to certain problems (i.e., constructions of objects having a certain 5771: 5660: 5209: 2829: 8061: 10808: 14910: 13287:{\displaystyle {\begin{aligned}\Phi \Psi g&=G(\varepsilon _{X})\circ GF(g)\circ \eta _{Y}\\&=G(\varepsilon _{X})\circ \eta _{GX}\circ g\\&=1_{GX}\circ g=g\end{aligned}}} 13069:{\displaystyle {\begin{aligned}\Psi \Phi f&=\varepsilon _{X}\circ FG(f)\circ F(\eta _{Y})\\&=f\circ \varepsilon _{FY}\circ F(\eta _{Y})\\&=f\circ 1_{FY}=f\end{aligned}}} 3344: 5710: 3514: 9095: 9046: 8211:
in predicate logics is in forming propositions and also in expressing sophisticated predicates by closing formulas with possibly more variables. For example, consider a predicate
6962:-bilinear product with (r,0)(0,1) = (0,1)(r,0) = (r,0), (r,0)(s,0) = (rs,0), (0,1)(0,1) = (0,1). This constructs a left adjoint to the functor taking a ring to the underlying rng. 6386: 5578: 5513: 15792: 9719: 9260: 6130: 2299:
The definition via counit–unit adjunction is convenient for proofs about functors which are known to be adjoint, because they provide formulas that can be directly manipulated.
1083: 5065: 15271: 10727: 10674: 10640: 8899: 8868: 5089: 3689: 3011: 1043: 1019: 991: 967: 817: 641: 301: 257: 123: 99: 10328: 8998: 8783: 11031: 11009: 10696: 10523: 9899: 9828: 9754: 9489: 9289: 8837: 8810: 6076: 9639: 7269:
be the category of pointed commutative rings with unity (pairs (A,a) where A is a ring, a ∈ A and morphisms preserve the distinguished elements). The forgetful functor G:
3466: 3425: 2781: 2740: 8925: 8087: 6342: 5318: 1710: 10771: 10567: 9674: 8508: 8481: 8236: 8007: 4761: 1358: 940: 14467: 10474: 10454: 8613: 3577: 3110: 2899: 2425: 1213: 12668: 11051: 7004: 14752: 10496:
The twin fact in probability can be understood as an adjunction: that expectation commutes with affine transform, and that the expectation is in some sense the best
9925: 9594: 8750: 8548: 6210: 5939: 5150: 1847:(which are also found in every area of mathematics), and the general adjoint functor theorems giving conditions under which a given functor is a left/right adjoint. 14772: 10394: 9781: 9296: 8528: 5116: 3267: 2582: 313: 10587: 10434: 10414: 10368: 10348: 9954: 9848: 9801: 9215: 9195: 9175: 9155: 9135: 9115: 9018: 8965: 8945: 8724: 8704: 8581: 8454: 8434: 8414: 8296: 8276: 8256: 8127: 8107: 3836: 3816: 3796: 3776: 3753: 3729: 3709: 3545: 3384: 3364: 3287: 3238: 3218: 3198: 3178: 3154: 3134: 3075: 3051: 3031: 2867: 2699: 2679: 2602: 2553: 2533: 2513: 2493: 2469: 2449: 1760: 1740: 1630: 1573: 1553: 1533: 1510: 1490: 1470: 1446: 1426: 1402: 1382: 1280: 1259: 1239: 913: 887: 866: 840: 793: 617: 451: 431: 277: 233: 46:
may exhibit, intuitively corresponding to a weak form of equivalence between two related categories. Two functors that stand in this relationship are known as
11061:
There are hence numerous functors and natural transformations associated with every adjunction, and only a small portion is sufficient to determine the rest.
6524:. The universal property of the product group shows that Ξ  is right-adjoint to Ξ”. The counit of this adjunction is the defining pair of projection maps from 2328:
which are under consideration. Therefore it can be helpful to choose letters in alphabetical order according to whether they live in the "lefthand" category
14724:{\displaystyle {\begin{aligned}\eta '&=(\tau \ast \sigma )\circ \eta \\\varepsilon '&=\varepsilon \circ (\sigma ^{-1}\ast \tau ^{-1}).\end{aligned}}} 13407: 5368:. That is, however, something particular to the case of tensor product. In category theory the 'naturality' of the bijection is subsumed in the concept of a 5254:, which was at the time devoted to computations. Those faced with giving tidy, systematic presentations of the subject would have noticed relations such as 1818:, which is formally similar to the above relation between hom-sets. The analogy to adjoint maps of Hilbert spaces can be made precise in certain contexts. 4584: 4517: 529: 456: 9961: 7657:
that is known as soberification. Notably, the article also contains a detailed description of another adjunction that prepares the way for the famous
4008: 10188: 7010:
and 1 is an identity element. This construction gives a functor that is a left adjoint to the functor taking a monoid to the underlying semigroup.
15828:
Every monad arises from some adjunctionβ€”in fact, typically from many adjunctionsβ€”in the above fashion. Two constructions, called the category of
13608: 10091: 8303: 3903: 9385: 11961:{\displaystyle {\begin{aligned}1_{FY}&=\varepsilon _{FY}\circ F(\eta _{Y})\\1_{GX}&=G(\varepsilon _{X})\circ \eta _{GX}\end{aligned}}} 5222:
Note: The use of the prefix "co" in counit here is not consistent with the terminology of limits and colimits, because a colimit satisfies an
5027:{\displaystyle {\begin{aligned}1_{FY}&=\varepsilon _{FY}\circ F(\eta _{Y})\\1_{GX}&=G(\varepsilon _{X})\circ \eta _{GX}\end{aligned}}} 2841: 1945:
is also formulaic in this construction, since it is always the category of elements of the functor to which one is constructing an adjoint.
7197:
to rings. This functor is left adjoint to the functor that associates to a given ring its underlying multiplicative monoid. Similarly, the
6857:, again a consequence of the universal property of direct sums. The unit of this adjoint pair is the defining pair of inclusion maps from 712: 646: 8620: 10525:, with objects being the real numbers, and the morphisms being "affine functions evaluated at a point". That is, for any affine function 15875: 1879:
way is to adjoin an element '1' to the rng, adjoin all (and only) the elements which are necessary for satisfying the ring axioms (e.g.
2904: 16128: 9783:
is given by the direct image. Here is a characterization of this result, which matches more the logical interpretation: The image of
16027: 12029:
In particular, the equations above allow one to define Ξ¦, Ξ΅, and Ξ· in terms of any one of the three. However, the adjoint functors
9048:, the category of sets and functions, the canonical subobjects are the subset (or rather their canonical injections). The pullback 1834: 5834:
One can also verify directly that Ξ΅ and Ξ· are natural. Then, a direct verification that they form a counit–unit adjunction  
16413: 15506:
then it is the left adjoint in an adjoint equivalence of categories, i.e. an adjunction whose unit and counit are isomorphisms.
14165: 14064: 13985:{\displaystyle {\begin{aligned}\Phi _{Y,X}(f)=G(f)\circ \eta _{Y}\\\Phi _{Y,X}^{-1}(g)=\varepsilon _{X}\circ F(g)\end{aligned}}} 8132: 5167:
These equations are useful in reducing proofs about adjoint functors to algebraic manipulations. They are sometimes called the
175: 135: 1765: 7678:
can be viewed as a category (where the elements of the poset become the category's objects and we have a single morphism from
3582: 1887:
in the ring), and impose no relations in the newly formed ring that are not forced by axioms. Moreover, this construction is
12037:
alone are in general not sufficient to determine the adjunction. The equivalence of these situations is demonstrated below.
15183:
Since many common constructions in mathematics are limits or colimits, this provides a wealth of information. For example:
14245: 12853:{\displaystyle {\begin{aligned}\Phi _{Y,X}(f)=G(f)\circ \eta _{Y}\\\Psi _{Y,X}(g)=\varepsilon _{X}\circ F(g)\end{aligned}}} 10919: 13726: 13533: 4489:{\displaystyle {\begin{aligned}\varepsilon &:FG\to 1_{\mathcal {C}}\\\eta &:1_{\mathcal {D}}\to GF\end{aligned}}} 1285: 15656: 14283: 9494: 8009:
is a unary predicate expressing some property, then a sufficiently strong set theory may prove the existence of the set
4866:{\displaystyle {\begin{aligned}1_{F}&=\varepsilon F\circ F\eta \\1_{G}&=G\varepsilon \circ \eta G\end{aligned}}} 1843:
uniqueness of a right adjoint for a given left adjoint, the fact that left/right adjoint functors respectively preserve
16787: 10813: 1894:
This is rather vague, though suggestive, and can be made precise in the language of category theory: a construction is
7549: 6042:. (Think of these words as placed in parentheses to indicate that they are independent generators.) The arrow   67: 16040: 16004: 15971: 6157: 5887: 13355: 12057:; in the sense of initial morphisms, one may construct the induced hom-set adjunction by doing the following steps. 6144:
it corresponds to (so this map is "dropping parentheses"). The composition of these maps is indeed the identity on
5837: 4696: 12234:
The commuting diagram of that factorization implies the commuting diagram of natural transformations, so Ξ· : 1
1635: 1578: 15156:
The most important property of adjoints is their continuity: every functor that has a left adjoint (and therefore
10880: 15710: 10964: 2607: 16838: 7553: 5731: 5620: 5182: 2786: 14820: 8012: 7728:
The partial order case collapses the adjunction definitions quite noticeably, but can provide several themes:
16121: 16070: 16032: 10776: 3292: 16325: 16280: 14434: 5673: 3471: 15836:
are two extremal solutions to the problem of constructing an adjunction that gives rise to a given monad.
9051: 9031: 1185:{\displaystyle \varphi _{XY}:\mathrm {hom} _{\mathcal {C}}(FY,X)\cong \mathrm {hom} _{\mathcal {D}}(Y,GX)} 16754: 16694: 15829: 6355: 5352:. It can be seen to be natural on the basis, firstly, that these are two alternative descriptions of the 16403: 15376:{\displaystyle \Phi _{Y,X}:\mathrm {hom} _{\mathcal {C}}(FY,X)\cong \mathrm {hom} _{\mathcal {D}}(Y,GX)} 5538: 5473: 1910:. Universal properties come in two types: initial properties and terminal properties. Since these are 16853: 16744: 16530: 16394: 16302: 15757: 14869: 9679: 9220: 7303: 6439: 6105: 6427:
have generally the same description as in the detailed description of the free group situation above.
5041: 16894: 16703: 16347: 16285: 16208: 15503: 15188: 10701: 10648: 10592: 8873: 8842: 7950: 7890: 7740: 7658: 6771: 6435: 6404:
it corresponds to ("dropping parentheses"). The composition of these maps is indeed the identity on
994: 20: 5070: 1024: 1000: 972: 948: 798: 622: 282: 238: 104: 80: 16734: 16690: 16295: 16114: 10303: 8970: 8755: 2292:
The definition via hom-sets makes symmetry the most apparent, and is the reason for using the word
2202:
yet; it is an important and not altogether trivial algebraic fact that such a left adjoint functor
1917:
The idea of using an initial property is to set up the problem in terms of some auxiliary category
11014: 10992: 10679: 10506: 9853: 9806: 9724: 9459: 9268: 8815: 8788: 7411:
that associates to every topological space its underlying set (forgetting the topology, that is).
6045: 16290: 16272: 15639: 15177: 15165: 9599: 7736: 7732:
adjunctions may not be dualities or isomorphisms, but are candidates for upgrading to that status
7713:
As is the case for Galois groups, the real interest lies often in refining a correspondence to a
6783: 6451: 6443: 5235: 3430: 3389: 2745: 2704: 2050:
is a ring map (which preserves the identity). (Note that this is precisely the definition of the
1844: 10183:
The right adjoint to the inverse image functor is given (without doing the computation here) by
8904: 8066: 6317: 5297: 1686: 16780: 16497: 16263: 16243: 16166: 16096: 15230: 14531: 12251: 11147: 10732: 10528: 9644: 8486: 8459: 8214: 7985: 7857: 7840:
multiplication, but in situations where this is not possible, we often attempt to construct an
7833: 7383: 6295:{\displaystyle GX{\xrightarrow {\;\eta _{GX}\;}}GFGX{\xrightarrow {\;G(\varepsilon _{X})\,}}GX} 6024:{\displaystyle FY{\xrightarrow {\;F(\eta _{Y})\;}}FGFY{\xrightarrow {\;\varepsilon _{FY}\,}}FY} 4740: 4400: 3657: 2979: 2371:, and whenever possible such things will be referred to in order from left to right (a functor 1911: 1340: 919: 410: 15921: 14440: 10459: 10439: 9369:{\displaystyle {\operatorname {Hom} }(\exists _{f}S,T)\cong {\operatorname {Hom} }(S,f^{*}T),} 8586: 3550: 3083: 2872: 2398: 1198: 16868: 16379: 16218: 12653: 11036: 10500:
to the problem of finding a real-valued approximation to a distribution on the real numbers.
7714: 7675: 7624: 7461: 7345: 7100: 6989: 6909: 5337: 15596:
In a sense, then, adjoints are "generalized" inverses. Note however that a right inverse of
14737: 13296:
hence ΦΨ is the identity transformation. Thus Φ is a natural isomorphism with inverse Φ = Ψ.
9904: 9573: 8729: 8533: 7364:. For the case of finitary algebraic structures, the existence by itself can be referred to 5515:  be the set map given by "inclusion of generators". This is an initial morphism from 5125: 399:{\displaystyle \mathrm {hom} _{\mathcal {C}}(FY,X)\cong \mathrm {hom} _{\mathcal {D}}(Y,GX)} 16818: 16191: 16186: 16100: 16064: 14757: 10373: 9759: 8513: 7923:
which assigns to a category its set of connected components is left-adjoint to the functor
7853: 7606: 7379: 7190: 6917: 6822: 5670:
they correspond to, which exists by the universal property of free groups. Then each  
5348:; those two groups are not really identical but there is a way of identifying them that is 5094: 16050: 16014: 15168:
in the category theoretical sense); every functor that has a right adjoint (and therefore
12673:, we can construct a hom-set adjunction by finding the natural transformation Ξ¦ : hom 5589: 3523:
The existence of the unit, a universal morphism, can prove the existence of an adjunction.
3243: 2558: 1069:: one is taken directly from Latin, the other from Latin via French. In the classic text 8: 16535: 16483: 16409: 16213: 15410: 15209: 11120: 10874: 7969:
and uncurrying; in many special cases, they are also continuous and form a homeomorphism.
7861: 7593: 7221: 7210: 7202: 7198: 5369: 5251: 5250:
in 1958. Like many of the concepts in category theory, it was suggested by the needs of
4266: 3895: 2835: 2003: 453:. Naturality here means that there are natural isomorphisms between the pair of functors 15929: 16389: 16384: 16366: 16248: 16223: 15900: 15854: 15439: 15202: 14491: 14340: 13515:{\displaystyle \varepsilon _{X}=\Phi _{GX,X}^{-1}(1_{GX})\in \mathrm {hom} _{C}(FGX,X)} 12011: 11983: 10572: 10419: 10399: 10353: 10333: 9930: 9833: 9786: 9200: 9180: 9160: 9140: 9120: 9100: 9003: 8950: 8930: 8709: 8689: 8566: 8439: 8419: 8399: 8281: 8261: 8241: 8208: 8112: 8092: 7662: 7653:
describes an adjunction between the category of topological spaces and the category of
7529: 7446: 7353: 7307: 7253: 5404: 3821: 3801: 3781: 3761: 3738: 3714: 3694: 3530: 3369: 3349: 3272: 3223: 3203: 3183: 3163: 3157: 3139: 3119: 3060: 3036: 3016: 2852: 2684: 2664: 2587: 2538: 2518: 2498: 2478: 2472: 2454: 2434: 1899: 1872: 1745: 1725: 1615: 1558: 1538: 1518: 1495: 1475: 1455: 1431: 1411: 1387: 1367: 1265: 1244: 1224: 898: 872: 851: 825: 778: 602: 436: 416: 262: 218: 59: 15140:
Since there is also a natural way to define an identity adjunction between a category
7710:
and to inverse order-preserving bijections between the corresponding closed elements.
4272: 16848: 16773: 16698: 16635: 16623: 16525: 16450: 16445: 16399: 16181: 16176: 16036: 16022: 16000: 15967: 15959: 14267: 8551: 7695: 7582: 7492: 7491:. The suspension functor is therefore left adjoint to the loop space functor in the 7408: 7404: 7365: 7361: 7341: 7033: 6574: 6570: 6420: 5433: 5345: 4508: 2320:
at its foundation, and there are many components which live in one of two categories
1074: 126: 71: 10729:
as "affine functions evaluated at a distribution". That is, for any affine function
4280:
The vertical arrows in this diagram are those induced by composition. Formally, Hom(
1937:
solutionβ€”means something rigorous and recognisable, rather like the attainment of a
16863: 16833: 16828: 16808: 16659: 16545: 16520: 16455: 16440: 16435: 16374: 16171: 16046: 16010: 15942: 15890: 15833: 15550: 15246: 7722: 7707: 7457: 7432: 6714: 6578: 6505: 6447: 5398: 5353: 4216: 2058:
over the inclusion of unitary rings into rng.) The existence of a morphism between
1720: 24: 15928:, 1969. The notation is different nowadays; an easier introduction by Peter Smith 13400:
which defines families of initial and terminal morphisms, in the following steps:
4640:{\displaystyle G{\xrightarrow {\;\eta G\;}}GFG{\xrightarrow {\;G\varepsilon \,}}G} 4573:{\displaystyle F{\xrightarrow {\;F\eta \;}}FGF{\xrightarrow {\;\varepsilon F\,}}F} 2260:
This gives the intuition behind the fact that adjoint functors occur in pairs: if
16858: 16823: 16571: 16137: 15917: 7747: 7513: 7496: 7357: 7281: 2101:
can have more adjoined elements and/or more relations not imposed by axioms than
592:{\displaystyle {\mathcal {D}}(-,GX):{\mathcal {D}}\to \mathrm {Set^{\text{op}}} } 519:{\displaystyle {\mathcal {C}}(F-,X):{\mathcal {D}}\to \mathrm {Set^{\text{op}}} } 35: 10077:{\displaystyle \exists _{f}S=\{y\in Y\mid \exists (x\in f^{-1}).\,x\in S\;\}=f.} 7913:
form an adjoint pair. The unit and counit are natural isomorphisms in this case.
7006:{1} and defining a binary operation on it such that it extends the operation on 6871:
into the direct sum, and the counit is the additive map from the direct sum of (
4109:{\displaystyle \Phi _{Y,X}:\mathrm {hom} _{C}(FY,X)\to \mathrm {hom} _{D}(Y,GX)} 16873: 16608: 16603: 16587: 16550: 16540: 16460: 15991: 15145: 14275: 10436:. Note how the predicate determining the set is the same as above, except that 7845: 7640: 7567: 7420: 7311: 7206: 7045: 6981: 5321: 5176: 2051: 1922: 15417:), then any pair of adjoint functors between them are automatically additive. 10289:{\displaystyle \forall _{f}S=\{y\in Y\mid \forall (x\in f^{-1}).\,x\in S\;\}.} 7280:
has a left adjoint – it assigns to every ring R the pair (R,x) where R is the
16888: 16843: 16598: 16430: 16307: 16233: 16074: 7735:
closure operators may indicate the presence of adjunctions, as corresponding
7703: 7694:). A pair of adjoint functors between two partially ordered sets is called a 7650: 7510: 7349: 7337: 6941: 5287: 1868: 1716: 5159: 1871:(which is like a ring that might not have a multiplicative identity) into a 16352: 16253: 15751:
is just the unit Ξ· of the adjunction and the multiplication transformation
13845:
The naturality of Ξ¦ implies the naturality of Ξ΅ and Ξ·, and the two formulas
13708:{\displaystyle \eta _{Y}=\Phi _{Y,FY}(1_{FY})\in \mathrm {hom} _{D}(Y,GFY)} 10173:{\displaystyle \{y\in Y\mid \exists x.\,\psi _{f}(x,y)\land \phi _{S}(x)\}} 8555: 8385:{\displaystyle \{y\in Y\mid \exists x.\,\psi _{f}(x,y)\land \phi _{S}(x)\}} 7702:
Galois connection). See that article for a number of examples: the case of
7369: 6921: 6913: 6424: 14430:
An analogous statement characterizes those functors with a right adjoint.
6423:
which assigns to an algebraic object its underlying set. These algebraic
5179:. A way to remember them is to first write down the nonsensical equation 3991:{\displaystyle \Phi :\mathrm {hom} _{C}(F-,-)\to \mathrm {hom} _{D}(-,G-)} 1061: 1055: 16613: 16593: 16465: 16335: 16084: 15853:
Baez, John C. (1996). "Higher-Dimensional Algebra II: 2-Hilbert Spaces".
9442:{\displaystyle \exists _{f}S\subseteq T\leftrightarrow S\subseteq f^{-1}} 7654: 7224:
instead of the category of rings, to get the monoid and group rings over
6946:
This example was discussed in the motivation section above. Given a rng
6775: 6416: 4220: 1864: 31: 16645: 16583: 16196: 15904: 11307: 7849: 7480: 7475:
is naturally isomorphic to the space of homotopy classes of maps from
7386:. This example foreshadowed the general theory by about half a century. 7252:
from fields has a left adjointβ€”it assigns to every integral domain its
7205:
to rings, left adjoint to the functor that assigns to a given ring its
5413: 5386: 5247: 2226:, and pose the following (vague) question: is there a problem to which 63: 16:
Relationship between two functors abstracting many common constructions
16080: 15859: 7762:
the power set of the set of all mathematical structures. For a theory
7721:
order isomorphism). A treatment of Galois theory along these lines by
16639: 16330: 15414: 15195: 9217:. It therefore turns out to be (in bijection with) the inverse image 8683: 7927:
which assigns to a set the discrete category on that set. Moreover,
6967: 6767: 4198: 768:{\displaystyle {\mathcal {D}}(Y,G-):{\mathcal {C}}\to \mathrm {Set} } 702:{\displaystyle {\mathcal {C}}(FY,-):{\mathcal {C}}\to \mathrm {Set} } 304: 15895: 15094: 15065: 14988: 14955: 14782:
Adjunctions can be composed in a natural fashion. Specifically, if γ€ˆ
12862:
The transformations Ξ¦ and Ξ¨ are natural because Ξ· and Ξ΅ are natural.
12618: 8671:{\displaystyle f^{*}:{\text{Sub}}(Y)\longrightarrow {\text{Sub}}(X)} 7241:
of integral domains with injective morphisms. The forgetful functor
6261: 6225: 5996: 5954: 4622: 4596: 4555: 4529: 2120:, that is, that there is a morphism from it to any other element of 1891:
in the sense that it works in essentially the same way for any rng.
16708: 16340: 16238: 16088: 14270:, then the functors with left adjoints can be characterized by the 10483: 7966: 7333: 6779: 5238:
where it looks like the insertion of the identity 1 into a monoid.
5219:
in one of the two simple ways which make the compositions defined.
4224: 2171:
has an identity and considering it simply as a rng, so essentially
1938: 16106: 7725:
was influential in the recognition of the general structure here.
7372:; naturally there is also a proof adapted to category theory, too. 6038:
is the free group generated freely by the words of the free group
16796: 16678: 16668: 16317: 16228: 16092: 15818: 14286:
and a certain smallness condition is satisfied: for every object
11081: 6396:
which underlies the group homomorphism sending each generator of
4373: 3866: 3852: 1907: 1066: 43: 16765: 15517:, Ξ΅, η〉 extends an equivalence of certain subcategories. Define 15450:. Conversely, if there exists a universal morphism to a functor 12040: 8785:. If this functor has a left- or right adjoint, they are called 7706:
of course is a leading one. Any Galois connection gives rise to
2969:{\displaystyle \epsilon _{X}\circ F(G(f))=f\circ \epsilon _{X'}} 16673: 15144:
and itself, one can then form a category whose objects are all
13087:
is a functor, that Ξ· is natural, and the counit–unit equation 1
12871:
is a functor, that Ξ΅ is natural, and the counit–unit equation 1
7935:
which assigns to each category its set of objects, and finally
7194: 6977: 5662:  be the group homomorphism which sends the generators of 2367:, Ξ· will consistently denote things which live in the category 2351:, Ξ΅ will consistently denote things which live in the category 2336:, and also to write them down in this order whenever possible. 2284:
There are various equivalent definitions for adjoint functors:
2245:
is, in a certain rigorous sense, equivalent to the notion that
2151:
denote the above process of adjoining an identity to a rng, so
1632:
a right adjoint because it is applied to the right argument of
15201:
every right adjoint functor between two abelian categories is
13300: 7943:
which assigns to each set the indiscrete category on that set.
16555: 15208:
every left adjoint functor between two abelian categories is
14923:
with unit and counit given respectively by the compositions:
14754:
denotes vertical composition of natural transformations, and
9756:. We conclude that left adjoint to the inverse image functor 7758:
to be the set of all logical theories (axiomatizations), and
6344:  is the "inclusion of generators" set map from the set 5118:
denotes the identity natural transformation from the functor
2143:
can be expressed simultaneously by saying that it defines an
2135:
The two facts that this method of turning rngs into rings is
1575:
a left adjoint because it is applied to the left argument of
1492:
may have itself a right adjoint that is quite different from
11318:
The transformations Ξ΅, Ξ·, and Ξ¦ are related by the equations
8483:-related, and which itself is characterized by the property 7336:, the point of departure is to observe that the category of 6411: 15990:
AdΓ‘mek, JiΕ™Γ­; Herrlich, Horst; Strecker, George E. (1990).
9901:
is non-empty. This works because it neglects exactly those
9291:, let us figure out the left adjoint, which is defined via 6950:, a multiplicative identity element can be added by taking 3080:
Similarly, we may define right-adjoint functors. A functor
14469:
is a functor between locally presentable categories, then
14223:{\displaystyle 1_{GX}=G(\varepsilon _{X})\circ \eta _{GX}} 14160:
in the first formula gives the second counit–unit equation
14122:{\displaystyle 1_{FY}=\varepsilon _{FY}\circ F(\eta _{Y})} 14057:
in the second formula gives the first counit–unit equation
11825:
The transformations Ξ΅, Ξ· satisfy the counit–unit equations
9157:
is characterized as the largest set which knows all about
8195:{\displaystyle \phi _{T}(y)=\phi _{Y}(y)\land \varphi (y)} 205:{\displaystyle G:{\mathcal {C}}\rightarrow {\mathcal {D}}} 165:{\displaystyle F:{\mathcal {D}}\rightarrow {\mathcal {C}}} 15386:
are, in fact, isomorphisms of abelian groups. Dually, if
7965:
has a right adjoint –. This pair is often referred to as
1811:{\displaystyle \langle Ty,x\rangle =\langle y,Ux\rangle } 15932:, which also attribute the concept to the article cited. 7639:. Here a more subtle point is that the left adjoint for 4355: 3647:{\displaystyle G(F(g))\circ \eta _{Y}=\eta _{Y'}\circ g} 2383:
can be thought of as "living" where its outputs are, in
1921:, so that the problem at hand corresponds to finding an 15593:
and yield inverse equivalences of these subcategories.
15265:
is also an additive functor and the hom-set bijections
7778:) be the set of all structures that satisfy the axioms 15989: 14569:, Ξ΅, η〉 is an adjunction (with counit–unit (Ξ΅,Ξ·)) and 6713:
be the functor which assigns to each homomorphism its
4693:, and may indicate this relationship by writing   1914:
notions, it is only necessary to discuss one of them.
1855:
In a sense, an adjoint functor is a way of giving the
15760: 15713: 15659: 15274: 14932: 14872: 14823: 14760: 14740: 14613: 14443: 14168: 14067: 13855: 13798:
The bijectivity and naturality of Ξ¦ imply that each (
13729: 13611: 13536: 13410: 13358: 13123: 12905: 12731: 12656: 11835: 11328: 11039: 11017: 10995: 10967: 10954:{\displaystyle \mathbb {E} :\mu \mapsto \mathbb {E} } 10922: 10883: 10816: 10779: 10735: 10704: 10682: 10651: 10595: 10575: 10531: 10509: 10462: 10442: 10422: 10402: 10376: 10356: 10336: 10306: 10191: 10094: 9964: 9933: 9907: 9856: 9836: 9809: 9789: 9762: 9727: 9682: 9647: 9602: 9576: 9497: 9462: 9388: 9299: 9271: 9223: 9203: 9183: 9163: 9143: 9123: 9103: 9054: 9034: 9006: 8973: 8953: 8933: 8907: 8876: 8845: 8818: 8791: 8758: 8732: 8712: 8692: 8623: 8589: 8569: 8536: 8516: 8489: 8462: 8442: 8422: 8402: 8306: 8284: 8264: 8244: 8217: 8135: 8115: 8095: 8069: 8015: 7988: 6992: 6358: 6320: 6213: 6160: 6108: 6048: 5942: 5890: 5840: 5734: 5676: 5623: 5541: 5476: 5300: 5185: 5128: 5097: 5073: 5044: 4901: 4786: 4743: 4699: 4587: 4520: 4411: 4223:. Explicitly, the naturality of Ξ¦ means that for all 4011: 3906: 3824: 3804: 3784: 3764: 3741: 3717: 3697: 3660: 3585: 3553: 3533: 3474: 3433: 3392: 3372: 3352: 3295: 3275: 3246: 3226: 3206: 3186: 3166: 3142: 3122: 3086: 3063: 3039: 3019: 2982: 2907: 2875: 2855: 2789: 2748: 2707: 2687: 2667: 2610: 2590: 2561: 2541: 2521: 2501: 2481: 2457: 2437: 2401: 2390: 1850: 1768: 1748: 1728: 1689: 1638: 1618: 1581: 1561: 1541: 1521: 1498: 1478: 1458: 1434: 1414: 1390: 1370: 1343: 1288: 1268: 1247: 1227: 1201: 1086: 1027: 1003: 975: 951: 922: 901: 875: 854: 828: 801: 781: 715: 649: 625: 605: 532: 459: 439: 419: 316: 285: 265: 241: 221: 178: 138: 107: 83: 15430:
As stated earlier, an adjunction between categories
11251:
such that the diagrams below commute, and for every
8530:
of two sets directly corresponds to the conjunction
8063:
of terms that fulfill the property. A proper subset
6837:
is the functor which assigns to every abelian group
3845: 2213: 1077:
makes a distinction between the two. Given a family
13788:{\displaystyle 1_{FY}\in \mathrm {hom} _{C}(FY,FY)} 13595:{\displaystyle 1_{GX}\in \mathrm {hom} _{D}(GX,GX)} 12265:
on morphisms preserves compositions and identities.
5720:, because any group homomorphism from a free group 5226:property whereas the counit morphisms will satisfy 1330:{\displaystyle \mathrm {hom} _{\mathcal {C}}(FY,X)} 15786: 15740: 15686:{\displaystyle T:{\mathcal {D}}\to {\mathcal {D}}} 15685: 15375: 15122: 14904: 14852: 14766: 14746: 14723: 14461: 14222: 14121: 13984: 13787: 13707: 13594: 13514: 13388: 13286: 13068: 12852: 12662: 11960: 11813: 11045: 11025: 11003: 10981: 10953: 10908: 10862: 10802: 10765: 10721: 10690: 10668: 10634: 10581: 10561: 10517: 10468: 10448: 10428: 10408: 10388: 10362: 10342: 10322: 10288: 10172: 10076: 9948: 9919: 9893: 9842: 9822: 9795: 9775: 9748: 9713: 9668: 9633: 9588: 9563:{\displaystyle S\subseteq f^{-1}]\subseteq f^{-1}} 9562: 9483: 9441: 9368: 9283: 9254: 9209: 9189: 9169: 9149: 9129: 9109: 9089: 9040: 9012: 8992: 8959: 8939: 8919: 8893: 8862: 8831: 8804: 8777: 8744: 8718: 8698: 8670: 8607: 8575: 8542: 8522: 8502: 8475: 8448: 8428: 8408: 8384: 8290: 8270: 8250: 8230: 8194: 8121: 8101: 8081: 8055: 8001: 7661:of sober spaces and spatial locales, exploited in 7614:from the category of sheaves of abelian groups on 6998: 6380: 6336: 6294: 6191: 6124: 6070: 6023: 5921: 5870: 5765: 5704: 5654: 5572: 5507: 5312: 5203: 5144: 5110: 5083: 5059: 5026: 4865: 4755: 4729: 4639: 4572: 4488: 4108: 3990: 3830: 3810: 3790: 3770: 3747: 3723: 3703: 3683: 3646: 3571: 3539: 3508: 3460: 3419: 3378: 3358: 3338: 3281: 3261: 3232: 3212: 3192: 3172: 3148: 3128: 3104: 3069: 3045: 3025: 3005: 2968: 2893: 2861: 2834:The latter equation is expressed by the following 2823: 2775: 2734: 2693: 2673: 2653: 2596: 2576: 2547: 2527: 2507: 2487: 2463: 2443: 2419: 2198:Note however that we haven't actually constructed 2167:denote the process of β€œforgettingβ€³ whether a ring 1827:The slogan is "Adjoint functors arise everywhere". 1810: 1754: 1734: 1704: 1661: 1624: 1604: 1567: 1547: 1527: 1504: 1484: 1464: 1440: 1420: 1396: 1376: 1352: 1329: 1274: 1253: 1233: 1207: 1184: 1037: 1013: 985: 961: 934: 907: 881: 860: 834: 811: 787: 767: 701: 635: 611: 591: 518: 445: 425: 398: 295: 271: 251: 227: 204: 164: 117: 93: 15993:Abstract and Concrete Categories. The joy of cats 15883:Transactions of the American Mathematical Society 12619:counit–unit adjunction induces hom-set adjunction 10863:{\displaystyle (\mu ,f):\mu \to \mu \circ f^{-1}} 8510:. Set theoretic operations like the intersection 6762: 16886: 8202:expressing a strictly more restrictive property. 7618:to the category of sheaves of abelian groups on 6782:are all examples of the categorical notion of a 6450:are all examples of the categorical notion of a 6034:should be the identity. The intermediate group 77:By definition, an adjunction between categories 16035:. Vol. 5 (2nd ed.). Springer-Verlag. 14915:More precisely, there is an adjunction between 13349:-), one can construct a counit–unit adjunction 10370:'s with the property that the inverse image of 6430: 6192:{\displaystyle 1_{G}=G\varepsilon \circ \eta G} 5922:{\displaystyle 1_{F}=\varepsilon F\circ F\eta } 5246:The idea of adjoint functors was introduced by 5175:because of the appearance of the corresponding 3200:. Spelled out, this means that for each object 2515:. Spelled out, this means that for each object 1859:solution to some problem via a method which is 15198:of objects yields the coproduct of the images; 13389:{\displaystyle (\varepsilon ,\eta ):F\dashv G} 10916:, and the expectation defines another functor 6976:, we can add an identity element and obtain a 6306:should be the identity. The intermediate set 5871:{\displaystyle (\varepsilon ,\eta ):F\dashv G} 4730:{\displaystyle (\varepsilon ,\eta ):F\dashv G} 1821: 16781: 16122: 16087:. Manipulation and visualization of objects, 15485: 15413:(i.e. preadditive categories with all finite 12647:, and a counit–unit adjunction (Ξ΅, Ξ·) : 12041:Universal morphisms induce hom-set adjunction 10698:with finite expectation. Define morphisms on 7596:(of sets, or abelian groups, or rings...) on 5462:is just the underlying set of the free group 5067:denotes the identify functor on the category 3758:It is true, as the terminology implies, that 1972:a ring having a multiplicative identity. The 1662:{\displaystyle \mathrm {hom} _{\mathcal {D}}} 1605:{\displaystyle \mathrm {hom} _{\mathcal {C}}} 1555:has a right adjoint" are equivalent. We call 15191:of objects yields the product of the images; 12270:Construct a natural isomorphism Ξ¦ : hom 10909:{\displaystyle \delta :x\mapsto \delta _{x}} 10383: 10377: 10280: 10257: 10251: 10208: 10167: 10095: 10053: 10030: 10024: 9981: 9879: 9873: 9000:and returns the thereby specified subset of 8379: 8307: 8050: 8022: 7643:will differ from that for sheaves (of sets). 7600:to the corresponding category of sheaves on 7528:be the inclusion functor to the category of 6924:of groups and by the disjoint union of sets. 6552:which define the limit, and the unit is the 5580:  via a unique group homomorphism from 5152:denotes the identity morphism of the object 1805: 1790: 1784: 1769: 15741:{\displaystyle \eta :1_{\mathcal {D}}\to T} 15614:) need not be a right (or left) adjoint of 13301:Hom-set adjunction induces all of the above 11314:From this assertion, one can recover that: 8583:in a category with pullbacks. Any morphism 4766:In equation form, the above conditions on ( 2304:repeated separately in every subject area. 1048: 16788: 16774: 16750: 16740: 16496: 16129: 16115: 15425: 12608:, and then Ξ¦ is natural in both arguments. 12257:Uniqueness of that factorization and that 12173:) is an initial morphism, then factorize Ξ· 10982:{\displaystyle \mathbb {E} \dashv \delta } 10279: 10052: 7397:A functor with a left and a right adjoint. 6262: 6240: 6226: 5997: 5975: 5955: 5803:correspond precisely to maps from the set 4623: 4604: 4597: 4556: 4537: 4530: 2654:{\displaystyle \epsilon _{X}:F(G(X))\to X} 2108:. Therefore, the assertion that an object 19:For the construction in field theory, see 16073:– seven short lectures on adjunctions by 15894: 15858: 15783: 12132:on objects and the family of morphisms Ξ·. 11761: 11760: 11648: 11647: 11530: 11529: 11412: 11411: 11019: 10997: 10969: 10938: 10924: 10793: 10712: 10684: 10676:, the set of probability distribution on 10659: 10511: 10269: 10119: 10042: 8331: 7826:is right adjoint to the "syntax functor" 7552:. The unit of this adjoint pair yields a 7344:has a commutative monoid structure under 7076:is left adjoint to the forgetful functor 6412:Free constructions and forgetful functors 6282: 6094:to the corresponding word of length one ( 6011: 5766:{\displaystyle \varepsilon _{X}:FGX\to X} 5655:{\displaystyle \varepsilon _{X}:FGX\to X} 5204:{\displaystyle 1=\varepsilon \circ \eta } 4630: 4563: 2824:{\displaystyle \epsilon _{X}\circ F(g)=f} 2339:In this article for example, the letters 1863:. For example, an elementary problem in 16028:Categories for the Working Mathematician 16021: 14853:{\displaystyle F\circ F':E\rightarrow C} 14282:has a left adjoint if and only if it is 13078:hence ΨΦ is the identity transformation. 8682:on the category that is the preorder of 8056:{\displaystyle Y=\{y\mid \phi _{Y}(y)\}} 6469:the functor which assigns to each pair ( 6419:are all examples of a left adjoint to a 5795:Group homomorphisms from the free group 5590:universal property of the free group on 5158: 2845:Here the counit is a universal morphism. 1948:Back to our example: take the given rng 1835:Categories for the Working Mathematician 1071:Categories for the Working Mathematician 993:is somewhat akin to a "weak form" of an 23:. For the construction in topology, see 13329:, and a hom-set adjunction Ξ¦ : hom 10803:{\displaystyle \mu \in M(\mathbb {R} )} 7782:; for a set of mathematical structures 6593:of homomorphisms of abelian groups. If 2087:is at least as efficient a solution as 409:such that this family of bijections is 66:in algebra, or the construction of the 16887: 15187:applying a right adjoint functor to a 14534:. The same is true for left adjoints. 11056: 10088:Put this in analogy to our motivation 8726:(technically: monomorphism classes of 7931:is left-adjoint to the object functor 7893:, then we have an inverse equivalence 7360:; but there is the other option of an 7117:-module, then the tensor product with 6140:sending each generator to the word of 6132:  is the group homomorphism from 6078:  is the group homomorphism from 5609:is the free group generated freely by 5389:is a common and illuminating example. 4002:This specifies a family of bijections 3547:can be uniquely turned into a functor 3339:{\displaystyle \eta _{Y}:Y\to G(F(Y))} 1933:β€”the sense that the process finds the 16769: 16495: 16148: 16110: 15194:applying a left adjoint functor to a 15151: 15148:and whose morphisms are adjunctions. 14433:An important special case is that of 12261:is a functor implies that the map of 11301:such that the diagrams below commute: 8927:to quantify a relation expressed via 7564:Direct and inverse images of sheaves. 7560:into its Stoneβ€“ΔŒech compactification. 5705:{\displaystyle (GX,\varepsilon _{X})} 5408:be the functor assigning to each set 4356:Definition via counit–unit adjunction 3509:{\displaystyle G(f)\circ \eta _{Y}=g} 2849:In this situation, one can show that 2312:The theory of adjoints has the terms 2279: 307:between the respective morphism sets 125:is a pair of functors (assumed to be 15852: 15638:, Ξ΅, η〉 gives rise to an associated 14806:β€², Ξ΅β€², η′〉 is an adjunction between 14246:Formal criteria for adjoint functors 10350:is characterized as the full set of 9090:{\displaystyle f^{*}T=X\times _{Y}T} 9041:{\displaystyle \operatorname {Set} } 8947:over, the functor/quantifier closes 7973: 7848:is adjoint to the multiplication by 6908:Analogous examples are given by the 6748:with the kernel of the homomorphism 6728:be the functor which maps the group 5234:here is borrowed from the theory of 4507:of the adjunction (terminology from 4197:as functors. In fact, they are both 16136: 15873: 14476:has a right adjoint if and only if 14294:there exists a family of morphisms 12384:is a functor, then for any objects 11166:A natural transformation Ξ· : 1 8839:, respectively. They both map from 7794:) be the minimal axiomatization of 7201:construction yields a functor from 6928: 6891:) of the direct sum to the element 6381:{\displaystyle G(\varepsilon _{X})} 5712:  is a terminal morphism from 4219:). For details, see the article on 13: 15726: 15678: 15668: 15349: 15343: 15340: 15337: 15308: 15302: 15299: 15296: 15276: 15133:This new adjunction is called the 15107: 14944: 14604:β€², Ξ΅β€², η′〉 is an adjunction where 14486:has a left adjoint if and only if 13918: 13861: 13754: 13751: 13748: 13674: 13671: 13668: 13626: 13561: 13558: 13555: 13481: 13478: 13475: 13425: 13131: 13128: 12913: 12910: 12794: 12737: 11770: 11767: 11764: 11699: 11657: 11654: 11651: 11578: 11539: 11536: 11533: 11466: 11421: 11418: 11415: 11340: 11306: 10463: 10443: 10308: 10223: 10193: 10110: 9996: 9966: 9811: 9390: 9309: 8820: 8793: 8322: 7868: 7193:construction gives a functor from 5573:{\displaystyle \eta _{Y}:Y\to GFY} 5508:{\displaystyle \eta _{Y}:Y\to GFY} 5230:properties, and dually. The term 5076: 5051: 4650:are the identity transformations 1 4467: 4441: 4271: 4078: 4075: 4072: 4039: 4036: 4033: 4013: 3960: 3957: 3954: 3921: 3918: 3915: 3907: 3518: 2840: 2391:Definition via universal morphisms 1929:. This has an advantage that the 1851:Solutions to optimization problems 1653: 1647: 1644: 1641: 1596: 1590: 1587: 1584: 1303: 1297: 1294: 1291: 1158: 1152: 1149: 1146: 1117: 1111: 1108: 1105: 1030: 1006: 978: 954: 804: 761: 758: 755: 746: 718: 695: 692: 689: 680: 652: 628: 579: 575: 572: 563: 535: 506: 502: 499: 490: 462: 372: 366: 363: 360: 331: 325: 322: 319: 288: 244: 197: 187: 157: 147: 110: 86: 14: 16906: 16795: 16083:is a category theory package for 16058: 15787:{\displaystyle \mu :T^{2}\to T\,} 14905:{\displaystyle G'\circ G:C\to E.} 14790:, Ξ΅, η〉 is an adjunction between 14490:preserves small limits and is an 11183:An equivalent formulation, where 11011:is the left adjoint, even though 9714:{\displaystyle S\subseteq f^{-1}} 9255:{\displaystyle f^{-1}\subseteq X} 7556:map from every topological space 7290:. Consider the inclusion functor 7187:From monoids and groups to rings. 6125:{\displaystyle \varepsilon _{FY}} 5773:  via a unique set map from 3846:Definition via Hom-set adjunction 2214:Symmetry of optimization problems 945:An adjunction between categories 62:), such as the construction of a 16749: 16739: 16730: 16729: 16482: 16149: 15420: 15390:is additive with a left adjoint 14774:denotes horizontal composition. 13795:  is the identity morphism. 13602:  is the identity morphism. 12323:) is an initial morphism, then Ξ¦ 12073:and a natural transformation Ξ·. 8238:with two open variables of sort 8129:is characterized by a predicate 8089:and the associated injection of 7698:(or, if it is contravariant, an 6199:  says that for each group 5060:{\displaystyle 1_{\mathcal {C}}} 2742:there exists a unique morphism 2230:is the most efficient solution? 643:, and also the pair of functors 15478:(equivalently, every object of 14596:are natural isomorphisms then γ€ˆ 14018:(which completely determine Ξ¦). 12380:Ξ· is a natural transformation, 10722:{\displaystyle M(\mathbb {R} )} 10669:{\displaystyle M(\mathbb {R} )} 10635:{\displaystyle (r,f):r\to f(r)} 9927:which are in the complement of 8901:. Very roughly, given a domain 8894:{\displaystyle {\text{Sub}}(Y)} 8863:{\displaystyle {\text{Sub}}(X)} 7836:is (in general) the attempt to 7380:representation theory of groups 7310:. It has a left adjoint called 6152:The second counit–unit equation 3427:there exists a unique morphism 1715:The terminology comes from the 1195:of hom-set bijections, we call 15953: 15935: 15911: 15867: 15846: 15777: 15732: 15673: 15542:is an isomorphism, and define 15370: 15355: 15329: 15314: 15137:of the two given adjunctions. 14893: 14844: 14777: 14711: 14679: 14645: 14633: 14453: 14435:locally presentable categories 14201: 14188: 14116: 14103: 13975: 13969: 13947: 13941: 13897: 13891: 13882: 13876: 13830:) is an initial morphism from 13808:) is a terminal morphism from 13782: 13764: 13702: 13684: 13660: 13644: 13589: 13571: 13509: 13491: 13467: 13451: 13371: 13359: 13220: 13207: 13178: 13172: 13160: 13147: 13024: 13011: 12973: 12960: 12951: 12945: 12843: 12837: 12815: 12809: 12773: 12767: 12758: 12752: 12084:, choose an initial morphism ( 12045:Given a right adjoint functor 11935: 11922: 11892: 11879: 11804: 11801: 11795: 11780: 11733: 11717: 11691: 11682: 11676: 11667: 11620: 11604: 11570: 11567: 11561: 11549: 11506: 11500: 11487: 11481: 11452: 11443: 11437: 11431: 11401: 11395: 11369: 11363: 10948: 10942: 10934: 10893: 10838: 10829: 10817: 10797: 10789: 10745: 10739: 10716: 10708: 10663: 10655: 10629: 10623: 10617: 10608: 10596: 10541: 10535: 10491: 10263: 10260: 10248: 10226: 10164: 10158: 10142: 10130: 10068: 10062: 10036: 10033: 10021: 9999: 9943: 9937: 9882: 9870: 9737: 9731: 9708: 9702: 9657: 9651: 9628: 9622: 9557: 9551: 9532: 9529: 9523: 9517: 9472: 9466: 9436: 9430: 9408: 9360: 9338: 9327: 9305: 9243: 9237: 8888: 8882: 8857: 8851: 8736: 8665: 8659: 8651: 8648: 8642: 8599: 8376: 8370: 8354: 8342: 8278:. Using a quantifier to close 8189: 8183: 8174: 8168: 8152: 8146: 8047: 8041: 6763:Colimits and diagonal functors 6375: 6362: 6310:is just the underlying set of 6279: 6266: 6065: 6052: 5972: 5959: 5929:  says that for each set 5882:The first counit–unit equation 5853: 5841: 5757: 5699: 5677: 5646: 5558: 5493: 5436:, which assigns to each group 5380: 5336:,–) (this is now known as the 5163:String diagram for adjunction. 5084:{\displaystyle {\mathcal {C}}} 5001: 4988: 4958: 4945: 4712: 4700: 4673:In this situation we say that 4511:), such that the compositions 4473: 4432: 4103: 4088: 4067: 4064: 4049: 3985: 3970: 3949: 3946: 3931: 3670: 3604: 3601: 3595: 3589: 3563: 3484: 3478: 3452: 3449: 3443: 3414: 3408: 3402: 3333: 3330: 3324: 3318: 3312: 3256: 3250: 3096: 2997: 2939: 2936: 2930: 2924: 2885: 2812: 2806: 2770: 2764: 2758: 2726: 2723: 2717: 2645: 2642: 2639: 2633: 2627: 2571: 2565: 2411: 2307: 1324: 1309: 1179: 1164: 1138: 1123: 1038:{\displaystyle {\mathcal {D}}} 1014:{\displaystyle {\mathcal {C}}} 986:{\displaystyle {\mathcal {D}}} 962:{\displaystyle {\mathcal {C}}} 812:{\displaystyle {\mathcal {D}}} 751: 738: 723: 685: 672: 657: 636:{\displaystyle {\mathcal {C}}} 568: 555: 540: 495: 482: 467: 393: 378: 352: 337: 296:{\displaystyle {\mathcal {D}}} 252:{\displaystyle {\mathcal {C}}} 192: 152: 118:{\displaystyle {\mathcal {D}}} 94:{\displaystyle {\mathcal {C}}} 1: 16033:Graduate Texts in Mathematics 15983: 15964:Sheaves in Geometry and Logic 15216: 14497: 14234: 10989:. (Somewhat disconcertingly, 10323:{\displaystyle \forall _{f}S} 8993:{\displaystyle X\times _{Y}T} 8778:{\displaystyle X\times _{Y}T} 7314:which assigns to every group 7216:and consider the category of 6972:Similarly, given a semigroup 6579:product of topological spaces 6508:which assigns to every group 5416:generated by the elements of 4165:In order to interpret Ξ¦ as a 2869:can be turned into a functor 1512:; see below for an example.) 15608:is naturally isomorphic to 1 15557:consisting of those objects 15528:consisting of those objects 14239: 11026:{\displaystyle \mathbb {E} } 11004:{\displaystyle \mathbb {E} } 10691:{\displaystyle \mathbb {R} } 10518:{\displaystyle \mathbb {R} } 9894:{\displaystyle f^{-1}\cap S} 9823:{\displaystyle \exists _{f}} 9749:{\displaystyle f\subseteq T} 9484:{\displaystyle f\subseteq T} 9284:{\displaystyle S\subseteq X} 9097:of an injection of a subset 8832:{\displaystyle \forall _{f}} 8805:{\displaystyle \exists _{f}} 7610:. It also induces a functor 7503:Stoneβ€“ΔŒech compactification. 7443:Suspensions and loop spaces. 7209:. One can also start with a 6577:, the product of rings, the 6431:Diagonal functors and limits 6071:{\displaystyle F(\eta _{Y})} 2661:such that for every object 2332:or the "righthand" category 7: 16424:Constructions on categories 15524:as the full subcategory of 15446:and one for each object in 14549:is naturally isomorphic to 14344:, such that every morphism 12693:-) in the following steps: 10645:Define a category based on 10503:Define a category based on 9634:{\displaystyle x\in f^{-1}} 7550:Stoneβ€“ΔŒech compactification 7390: 6966:Adjoining an identity to a 6940:Adjoining an identity to a 6388:  is the set map from 5523:, because any set map from 5375: 3461:{\displaystyle f:F(Y)\to X} 3420:{\displaystyle g:Y\to G(X)} 3346:such that for every object 2901:in a unique way such that 2776:{\displaystyle g:Y\to G(X)} 2735:{\displaystyle f:F(Y)\to X} 1822:Introduction and Motivation 68:Stoneβ€“ΔŒech compactification 42:is a relationship that two 10: 16911: 16531:Higher-dimensional algebra 15922:Adjointness in foundations 15486:Equivalences of categories 15438:gives rise to a family of 14262:admits a left adjoint. If 14243: 10416:is fully contained within 8920:{\displaystyle S\subset X} 8082:{\displaystyle T\subset Y} 7822:: the "semantics functor" 7746:a very general comment of 7304:category of abelian groups 7175:) for every abelian group 6933: 6821:) of abelian groups their 6520:) in the product category 6337:{\displaystyle \eta _{GX}} 5728:will factor through   5535:will factor through   5440:its underlying set. Then 5313:{\displaystyle -\otimes A} 5241: 3240:, there exists an object 2395:By definition, a functor 1705:{\displaystyle F\dashv G.} 1384:(p. 81). The functor 18: 16804: 16725: 16658: 16622: 16570: 16563: 16514: 16504: 16491: 16480: 16423: 16365: 16316: 16271: 16262: 16159: 16155: 16144: 15999:. John Wiley & Sons. 15625: 15504:equivalence of categories 15442:, one for each object in 10766:{\displaystyle f(x)=ax+b} 10562:{\displaystyle f(x)=ax+b} 9669:{\displaystyle f(x)\in T} 8503:{\displaystyle \phi _{S}} 8476:{\displaystyle \psi _{f}} 8231:{\displaystyle \psi _{f}} 8002:{\displaystyle \phi _{Y}} 7951:cartesian closed category 7891:equivalence of categories 7741:Kuratowski closure axioms 7669: 7284:with coefficients from R. 6671:) of morphisms such that 5811:: each homomorphism from 5588:. This is precisely the 4876:which mean that for each 4756:{\displaystyle F\dashv G} 3684:{\displaystyle g:Y\to Y'} 3006:{\displaystyle f:X'\to X} 2132:solution to our problem. 1515:In general, the phrases " 1353:{\displaystyle \varphi f} 935:{\displaystyle F\dashv G} 21:Adjunction (field theory) 15962:; Moerdijk, Ieke (1992) 15839: 15830:Eilenberg–Moore algebras 15704:. The unit of the monad 15646:, Ξ·, μ〉 in the category 15571:is an isomorphism. Then 14557:is also left adjoint to 14480:preserves small colimits 14462:{\displaystyle F:C\to D} 10961:, and they are adjoint: 10469:{\displaystyle \forall } 10449:{\displaystyle \exists } 9570:. Conversely, If for an 8608:{\displaystyle f:X\to Y} 7917:A series of adjunctions. 7352:out of this monoid, the 7179:, is a right adjoint to 7040:can be seen as a (left) 7024:are rings, and ρ : 5211:and then fill in either 4737: , or simply   4499:respectively called the 3572:{\displaystyle F:D\to C} 3105:{\displaystyle G:C\to D} 2894:{\displaystyle G:C\to D} 2555:there exists an object 2420:{\displaystyle F:D\to C} 2241:to the problem posed by 2147:. More explicitly: Let 1535:is a left adjoint" and " 1208:{\displaystyle \varphi } 1049:Terminology and notation 16341:Cokernels and quotients 16264:Universal constructions 16097:natural transformations 15874:Kan, Daniel M. (1958). 15426:Universal constructions 14561:β€². More generally, if γ€ˆ 14514:has two right adjoints 14272:adjoint functor theorem 12663:{\displaystyle \dashv } 12333:is a bijection, where Ξ¦ 12128:)). We have the map of 11046:{\displaystyle \delta } 7905:, and the two functors 7798:. We can then say that 7495:, an important fact in 6999:{\displaystyle \sqcup } 6807:assigns to every pair ( 6639:, then a morphism from 6086:sending each generator 5832:counit–unit adjunction. 4401:natural transformations 4364:between two categories 3857:between two categories 2239:most efficient solution 2218:It is also possible to 1065:are both used, and are 16839:Essentially surjective 16498:Higher category theory 16244:Natural transformation 15930:in these lecture notes 15805:. Dually, the triple γ€ˆ 15788: 15742: 15687: 15618:. Adjoints generalize 15377: 15231:preadditive categories 15124: 14906: 14854: 14768: 14748: 14747:{\displaystyle \circ } 14725: 14463: 14224: 14123: 13986: 13789: 13709: 13596: 13516: 13390: 13288: 13070: 12867:Using, in order, that 12854: 12664: 12252:natural transformation 12227:). This is the map of 11962: 11815: 11311: 11195:denotes any object of 11187:denotes any object of 11148:natural transformation 11047: 11027: 11005: 10983: 10955: 10910: 10864: 10804: 10767: 10723: 10692: 10670: 10636: 10583: 10563: 10519: 10470: 10450: 10430: 10410: 10390: 10364: 10344: 10324: 10290: 10174: 10078: 9950: 9921: 9920:{\displaystyle y\in Y} 9895: 9844: 9824: 9797: 9777: 9750: 9715: 9670: 9635: 9590: 9589:{\displaystyle x\in S} 9564: 9485: 9443: 9380:which here just means 9370: 9285: 9256: 9211: 9191: 9171: 9151: 9131: 9111: 9091: 9042: 9014: 8994: 8961: 8941: 8921: 8895: 8864: 8833: 8806: 8779: 8746: 8745:{\displaystyle T\to Y} 8720: 8700: 8672: 8609: 8577: 8563:So consider an object 8544: 8543:{\displaystyle \land } 8524: 8504: 8477: 8450: 8436:for which there is an 8430: 8410: 8386: 8298:, we can form the set 8292: 8272: 8252: 8232: 8196: 8123: 8103: 8083: 8057: 8003: 7427:, and a right adjoint 7384:induced representation 7330:The Grothendieck group 7234:Consider the category 7000: 6589:Consider the category 6382: 6338: 6296: 6193: 6126: 6072: 6025: 5923: 5878:  is as follows: 5872: 5789:) is an adjoint pair. 5767: 5706: 5656: 5574: 5527:to the underlying set 5509: 5314: 5205: 5164: 5146: 5145:{\displaystyle 1_{FY}} 5112: 5085: 5061: 5028: 4867: 4757: 4731: 4641: 4574: 4490: 4362:counit–unit adjunction 4277: 4265:the following diagram 4110: 3992: 3832: 3812: 3792: 3772: 3749: 3725: 3705: 3685: 3648: 3573: 3541: 3524: 3510: 3462: 3421: 3380: 3360: 3340: 3283: 3263: 3234: 3214: 3194: 3174: 3150: 3130: 3106: 3071: 3047: 3027: 3007: 2970: 2895: 2863: 2846: 2825: 2777: 2736: 2695: 2675: 2655: 2598: 2578: 2549: 2529: 2509: 2489: 2465: 2445: 2421: 2251:most difficult problem 2124:, means that the ring 1960:are rng homomorphisms 1952:, and make a category 1840: 1812: 1756: 1736: 1706: 1663: 1626: 1606: 1569: 1549: 1529: 1506: 1486: 1466: 1442: 1422: 1398: 1378: 1354: 1331: 1276: 1255: 1235: 1209: 1186: 1039: 1015: 987: 963: 936: 909: 883: 862: 836: 813: 789: 769: 703: 637: 613: 593: 520: 447: 427: 400: 297: 273: 253: 229: 206: 166: 119: 95: 15943:"Indiscrete category" 15789: 15743: 15688: 15579:can be restricted to 15462:from every object of 15378: 15249:with a right adjoint 15125: 14907: 14855: 14769: 14767:{\displaystyle \ast } 14749: 14726: 14464: 14225: 14124: 13987: 13790: 13710: 13597: 13517: 13391: 13289: 13071: 12855: 12665: 11963: 11816: 11310: 11048: 11028: 11006: 10984: 10956: 10911: 10865: 10805: 10768: 10724: 10693: 10671: 10637: 10584: 10564: 10520: 10471: 10451: 10431: 10411: 10391: 10389:{\displaystyle \{y\}} 10365: 10345: 10325: 10291: 10175: 10079: 9951: 9922: 9896: 9845: 9825: 9798: 9778: 9776:{\displaystyle f^{*}} 9751: 9716: 9671: 9636: 9591: 9565: 9486: 9444: 9371: 9286: 9257: 9212: 9192: 9177:and the injection of 9172: 9152: 9132: 9112: 9092: 9043: 9015: 8995: 8962: 8942: 8922: 8896: 8865: 8834: 8807: 8780: 8747: 8721: 8701: 8686:. It maps subobjects 8673: 8610: 8578: 8545: 8525: 8523:{\displaystyle \cap } 8505: 8478: 8451: 8431: 8411: 8387: 8293: 8273: 8253: 8233: 8197: 8124: 8104: 8084: 8058: 8004: 7676:partially ordered set 7625:inverse image functor 7592:from the category of 7376:Frobenius reciprocity 7001: 6883:(sending an element ( 6564:(mapping x to (x,x)). 6383: 6339: 6297: 6194: 6127: 6073: 6026: 5924: 5873: 5768: 5707: 5657: 5575: 5510: 5338:tensor-hom adjunction 5315: 5206: 5162: 5147: 5113: 5111:{\displaystyle 1_{F}} 5086: 5062: 5029: 4868: 4776:counit–unit equations 4758: 4732: 4642: 4575: 4491: 4275: 4169:, one must recognize 4111: 3993: 3833: 3813: 3793: 3773: 3750: 3726: 3706: 3686: 3649: 3574: 3542: 3522: 3511: 3463: 3422: 3381: 3361: 3341: 3284: 3264: 3235: 3215: 3195: 3175: 3151: 3131: 3114:right adjoint functor 3107: 3072: 3048: 3028: 3008: 2971: 2896: 2864: 2844: 2826: 2778: 2737: 2696: 2676: 2656: 2599: 2579: 2550: 2530: 2510: 2490: 2466: 2446: 2422: 2004:commutative triangles 1825: 1813: 1757: 1737: 1707: 1664: 1627: 1607: 1570: 1550: 1530: 1507: 1487: 1467: 1443: 1423: 1399: 1379: 1355: 1332: 1277: 1256: 1236: 1210: 1187: 1040: 1016: 988: 964: 937: 910: 891:right adjoint functor 884: 863: 837: 814: 790: 770: 704: 638: 614: 594: 521: 448: 428: 401: 298: 274: 254: 230: 215:and, for all objects 207: 167: 120: 96: 16367:Algebraic categories 16101:universal properties 15758: 15711: 15657: 15470:has a left adjoint. 15272: 15176:(i.e. commutes with 15164:(i.e. commutes with 15160:a right adjoint) is 14930: 14870: 14821: 14758: 14738: 14611: 14532:naturally isomorphic 14441: 14166: 14065: 13853: 13727: 13609: 13534: 13408: 13356: 13121: 12903: 12729: 12654: 12061:Construct a functor 11833: 11326: 11267:, there is a unique 11221:, there is a unique 11037: 11015: 10993: 10965: 10920: 10881: 10814: 10810:, define a morphism 10777: 10733: 10702: 10680: 10649: 10593: 10589:, define a morphism 10573: 10569:and any real number 10529: 10507: 10460: 10440: 10420: 10400: 10374: 10354: 10334: 10304: 10189: 10092: 9962: 9931: 9905: 9854: 9834: 9807: 9787: 9760: 9725: 9680: 9645: 9600: 9574: 9495: 9460: 9386: 9297: 9269: 9221: 9201: 9181: 9161: 9141: 9121: 9101: 9052: 9032: 9004: 8971: 8951: 8931: 8905: 8874: 8843: 8816: 8789: 8756: 8730: 8710: 8690: 8621: 8587: 8567: 8534: 8514: 8487: 8460: 8440: 8420: 8400: 8304: 8282: 8262: 8242: 8215: 8133: 8113: 8093: 8067: 8013: 7986: 7818:) logically implies 7752:syntax and semantics 7607:direct image functor 7403:be the functor from 7191:integral monoid ring 6990: 6740:is right adjoint to 6732:to the homomorphism 6483:) the product group 6356: 6318: 6211: 6158: 6106: 6098:) as a generator of 6046: 5940: 5888: 5838: 5781:. This means that ( 5732: 5674: 5621: 5539: 5474: 5385:The construction of 5332:was the functor hom( 5298: 5183: 5126: 5095: 5071: 5042: 4899: 4784: 4741: 4697: 4688:is right adjoint to 4585: 4518: 4409: 4153:is right adjoint to 4009: 3904: 3822: 3818:is right adjoint to 3802: 3782: 3762: 3739: 3715: 3695: 3658: 3583: 3551: 3531: 3472: 3431: 3390: 3370: 3350: 3293: 3273: 3262:{\displaystyle F(Y)} 3244: 3224: 3204: 3184: 3164: 3140: 3120: 3084: 3061: 3037: 3017: 2980: 2905: 2873: 2853: 2787: 2746: 2705: 2685: 2665: 2608: 2588: 2577:{\displaystyle G(X)} 2559: 2539: 2519: 2499: 2479: 2455: 2435: 2429:left adjoint functor 2399: 2272:is right adjoint to 2189:left adjoint functor 1766: 1746: 1726: 1687: 1636: 1616: 1579: 1559: 1539: 1519: 1496: 1476: 1456: 1432: 1412: 1388: 1368: 1341: 1286: 1266: 1245: 1225: 1199: 1084: 1025: 1001: 973: 949: 920: 899: 873: 852: 844:left adjoint functor 826: 799: 779: 713: 647: 623: 603: 530: 457: 437: 417: 314: 283: 263: 239: 219: 176: 136: 105: 81: 16536:Homotopy hypothesis 16214:Commutative diagram 15966:, Springer-Verlag. 15918:Lawvere, F. William 15440:universal morphisms 15411:additive categories 15172:a left adjoint) is 15098: 15080: 15008: 14964: 14863:is left adjoint to 14541:is left adjoint to 13940: 13450: 13083:Dually, using that 11603: 11362: 11121:natural isomorphism 11068:between categories 11057:Adjunctions in full 11033:is "forgetful" and 10877:defines a functor: 10875:Dirac delta measure 9830:is the full set of 7939:is left-adjoint to 7862:logical conjunction 7858:propositional logic 7632:is left adjoint to 7536:has a left adjoint 7509:be the category of 7415:has a left adjoint 7318:the quotient group 7232:Field of fractions. 7199:integral group ring 6853:is left adjoint to 6635:are two objects of 6497:, and let Ξ” : 6352:. The arrow   6314:. The arrow   6283: 6241: 6102:. The arrow   6012: 5976: 5793:Hom-set adjunction. 5666:to the elements of 5599:Terminal morphisms. 5444:is left adjoint to 5370:natural isomorphism 5286:in the category of 5252:homological algebra 5171:, or sometimes the 5169:triangle identities 4678:is left adjoint to 4631: 4605: 4564: 4538: 4167:natural isomorphism 4143:is left adjoint to 4138:In this situation, 3896:natural isomorphism 3778:is left adjoint to 3386:and every morphism 3116:if for each object 2836:commutative diagram 2701:and every morphism 2431:if for each object 2264:is left adjoint to 1832:Saunders Mac Lane, 1676:is left adjoint to 1221:adjunction between 64:free group on a set 16249:Universal property 16023:Mac Lane, Saunders 15960:Mac Lane, Saunders 15876:"Adjoint Functors" 15784: 15738: 15683: 15630:Every adjunction γ€ˆ 15509:Every adjunction γ€ˆ 15502:is one half of an 15401:Moreover, if both 15398:is also additive. 15373: 15152:Limit preservation 15120: 15118: 14902: 14850: 14764: 14744: 14721: 14719: 14492:accessible functor 14459: 14402:and some morphism 14367:can be written as 14327:where the indices 14250:Not every functor 14220: 14119: 13982: 13980: 13917: 13785: 13705: 13592: 13512: 13424: 13386: 13284: 13282: 13066: 13064: 12850: 12848: 12660: 11958: 11956: 11811: 11809: 11577: 11339: 11312: 11043: 11023: 11001: 10979: 10951: 10906: 10860: 10800: 10763: 10719: 10688: 10666: 10632: 10579: 10559: 10515: 10466: 10446: 10426: 10406: 10386: 10360: 10340: 10320: 10286: 10170: 10074: 9946: 9917: 9891: 9840: 9820: 9793: 9773: 9746: 9711: 9666: 9631: 9586: 9560: 9481: 9439: 9366: 9281: 9252: 9207: 9187: 9167: 9147: 9127: 9107: 9087: 9038: 9010: 8990: 8957: 8937: 8917: 8891: 8860: 8829: 8802: 8775: 8752:) to the pullback 8742: 8716: 8696: 8668: 8615:induces a functor 8605: 8573: 8550:of predicates. In 8540: 8520: 8500: 8473: 8446: 8426: 8406: 8382: 8288: 8268: 8248: 8228: 8192: 8119: 8099: 8079: 8053: 7999: 7947:Exponential object 7754:are adjoint: take 7663:pointless topology 7585:induces a functor 7583:topological spaces 7530:topological spaces 7447:topological spaces 7405:topological spaces 7354:Grothendieck group 7348:. One may make an 7308:category of groups 7254:field of fractions 6996: 6556:of a group X into 6554:diagonal inclusion 6400:to the element of 6378: 6334: 6292: 6189: 6122: 6068: 6021: 5919: 5868: 5763: 5702: 5652: 5613:, the elements of 5570: 5505: 5452:Initial morphisms. 5340:). The use of the 5310: 5201: 5165: 5142: 5108: 5081: 5057: 5024: 5022: 4863: 4861: 4753: 4727: 4637: 4570: 4486: 4484: 4278: 4244:and all morphisms 4106: 3988: 3828: 3808: 3788: 3768: 3745: 3721: 3701: 3681: 3644: 3569: 3537: 3525: 3506: 3458: 3417: 3376: 3356: 3336: 3279: 3259: 3230: 3210: 3190: 3170: 3158:universal morphism 3156:, there exists a 3146: 3126: 3102: 3067: 3043: 3023: 3003: 2976:for all morphisms 2966: 2891: 2859: 2847: 2821: 2773: 2732: 2691: 2671: 2651: 2594: 2574: 2545: 2525: 2505: 2485: 2473:universal morphism 2461: 2441: 2417: 2280:Formal definitions 1900:universal property 1898:if it satisfies a 1808: 1752: 1732: 1702: 1659: 1622: 1602: 1565: 1545: 1525: 1502: 1482: 1462: 1438: 1418: 1394: 1374: 1350: 1327: 1272: 1251: 1231: 1205: 1182: 1035: 1011: 983: 959: 932: 905: 879: 858: 832: 809: 785: 765: 699: 633: 609: 589: 516: 443: 423: 396: 293: 269: 249: 225: 202: 172:  and   162: 115: 91: 60:universal property 54:and the other the 16882: 16881: 16854:Full and faithful 16763: 16762: 16721: 16720: 16717: 16716: 16699:monoidal category 16654: 16653: 16526:Enriched category 16478: 16477: 16474: 16473: 16451:Quotient category 16446:Opposite category 16361: 16360: 15099: 15081: 15009: 14965: 14814:then the functor 14268:complete category 14132:and substituting 13106: 12885: 12604: 12580: 12565: 12553: 12542: 12521: 12506: 12495: 12484: 12478: 12370: 12246: 12184: 11984:terminal morphism 11199:, is as follows: 10582:{\displaystyle r} 10429:{\displaystyle S} 10409:{\displaystyle f} 10363:{\displaystyle y} 10343:{\displaystyle Y} 9949:{\displaystyle f} 9843:{\displaystyle y} 9796:{\displaystyle S} 9210:{\displaystyle Y} 9190:{\displaystyle T} 9170:{\displaystyle f} 9150:{\displaystyle f} 9130:{\displaystyle Y} 9110:{\displaystyle T} 9013:{\displaystyle Y} 8960:{\displaystyle X} 8940:{\displaystyle f} 8880: 8849: 8719:{\displaystyle Y} 8699:{\displaystyle T} 8657: 8640: 8576:{\displaystyle Y} 8552:categorical logic 8449:{\displaystyle x} 8429:{\displaystyle Y} 8409:{\displaystyle y} 8291:{\displaystyle X} 8271:{\displaystyle Y} 8251:{\displaystyle X} 8122:{\displaystyle Y} 8102:{\displaystyle T} 7974:Categorical logic 7810:) if and only if 7708:closure operators 7696:Galois connection 7493:homotopy category 7460:of maps from the 7366:universal algebra 7362:existence theorem 7342:topological space 7121:yields a functor 7052:yields a functor 7044:-module, and the 7034:ring homomorphism 6772:fibred coproducts 6571:cartesian product 6421:forgetful functor 6284: 6242: 6013: 5977: 5434:forgetful functor 5354:bilinear mappings 5346:abuse of notation 5173:zig-zag equations 4632: 4606: 4565: 4539: 4509:universal algebra 4325: 4321: 3831:{\displaystyle F} 3811:{\displaystyle G} 3791:{\displaystyle G} 3771:{\displaystyle F} 3748:{\displaystyle F} 3731:is then called a 3724:{\displaystyle G} 3704:{\displaystyle D} 3540:{\displaystyle F} 3379:{\displaystyle C} 3359:{\displaystyle X} 3282:{\displaystyle C} 3233:{\displaystyle D} 3213:{\displaystyle Y} 3193:{\displaystyle G} 3173:{\displaystyle Y} 3149:{\displaystyle D} 3129:{\displaystyle Y} 3070:{\displaystyle G} 3053:is then called a 3046:{\displaystyle F} 3026:{\displaystyle C} 2862:{\displaystyle G} 2694:{\displaystyle D} 2674:{\displaystyle Y} 2597:{\displaystyle D} 2548:{\displaystyle C} 2528:{\displaystyle X} 2508:{\displaystyle X} 2488:{\displaystyle F} 2464:{\displaystyle C} 2444:{\displaystyle X} 2222:with the functor 2210:actually exists. 1867:is how to turn a 1755:{\displaystyle U} 1735:{\displaystyle T} 1721:adjoint operators 1625:{\displaystyle G} 1568:{\displaystyle F} 1548:{\displaystyle F} 1528:{\displaystyle F} 1505:{\displaystyle F} 1485:{\displaystyle G} 1465:{\displaystyle F} 1441:{\displaystyle G} 1421:{\displaystyle G} 1397:{\displaystyle F} 1377:{\displaystyle f} 1275:{\displaystyle f} 1254:{\displaystyle G} 1234:{\displaystyle F} 908:{\displaystyle F} 895:right adjoint to 882:{\displaystyle G} 861:{\displaystyle G} 835:{\displaystyle F} 788:{\displaystyle Y} 612:{\displaystyle X} 585: 512: 446:{\displaystyle Y} 426:{\displaystyle X} 272:{\displaystyle Y} 228:{\displaystyle X} 72:topological space 16902: 16895:Adjoint functors 16790: 16783: 16776: 16767: 16766: 16753: 16752: 16743: 16742: 16733: 16732: 16568: 16567: 16546:Simplex category 16521:Categorification 16512: 16511: 16493: 16492: 16486: 16456:Product category 16441:Kleisli category 16436:Functor category 16281:Terminal objects 16269: 16268: 16204:Adjoint functors 16157: 16156: 16146: 16145: 16131: 16124: 16117: 16108: 16107: 16067: 16054: 16018: 15998: 15977: 15957: 15951: 15950: 15939: 15933: 15915: 15909: 15908: 15898: 15880: 15871: 15865: 15864: 15862: 15850: 15834:Kleisli category 15797:is given by ΞΌ = 15793: 15791: 15790: 15785: 15776: 15775: 15747: 15745: 15744: 15739: 15731: 15730: 15729: 15692: 15690: 15689: 15684: 15682: 15681: 15672: 15671: 15600:(i.e. a functor 15551:full subcategory 15382: 15380: 15379: 15374: 15354: 15353: 15352: 15346: 15313: 15312: 15311: 15305: 15290: 15289: 15247:additive functor 15146:small categories 15129: 15127: 15126: 15121: 15119: 15112: 15111: 15110: 15100: 15090: 15082: 15076: 15061: 15056: 15048: 15036: 15032: 15018: 15010: 15007: 14996: 14984: 14982: 14974: 14966: 14963: 14951: 14949: 14948: 14947: 14936: 14911: 14909: 14908: 14903: 14880: 14859: 14857: 14856: 14851: 14837: 14773: 14771: 14770: 14765: 14753: 14751: 14750: 14745: 14730: 14728: 14727: 14722: 14720: 14710: 14709: 14694: 14693: 14665: 14625: 14468: 14466: 14465: 14460: 14401: 14337: 14229: 14227: 14226: 14221: 14219: 14218: 14200: 14199: 14181: 14180: 14128: 14126: 14125: 14120: 14115: 14114: 14096: 14095: 14080: 14079: 13991: 13989: 13988: 13983: 13981: 13962: 13961: 13939: 13931: 13912: 13911: 13875: 13874: 13794: 13792: 13791: 13786: 13763: 13762: 13757: 13742: 13741: 13715:  for each 13714: 13712: 13711: 13706: 13683: 13682: 13677: 13659: 13658: 13643: 13642: 13621: 13620: 13601: 13599: 13598: 13593: 13570: 13569: 13564: 13549: 13548: 13522:  for each 13521: 13519: 13518: 13513: 13490: 13489: 13484: 13466: 13465: 13449: 13441: 13420: 13419: 13395: 13393: 13392: 13387: 13293: 13291: 13290: 13285: 13283: 13267: 13266: 13248: 13238: 13237: 13219: 13218: 13197: 13193: 13192: 13159: 13158: 13104: 13075: 13073: 13072: 13067: 13065: 13055: 13054: 13030: 13023: 13022: 13004: 13003: 12979: 12972: 12971: 12935: 12934: 12883: 12859: 12857: 12856: 12851: 12849: 12830: 12829: 12808: 12807: 12788: 12787: 12751: 12750: 12669: 12667: 12666: 12661: 12602: 12578: 12563: 12551: 12540: 12519: 12504: 12493: 12482: 12476: 12368: 12293:For each object 12244: 12182: 12076:For each object 12012:initial morphism 11967: 11965: 11964: 11959: 11957: 11953: 11952: 11934: 11933: 11911: 11910: 11891: 11890: 11872: 11871: 11852: 11851: 11820: 11818: 11817: 11812: 11810: 11779: 11778: 11773: 11752: 11751: 11732: 11731: 11716: 11715: 11666: 11665: 11660: 11639: 11638: 11619: 11618: 11602: 11594: 11548: 11547: 11542: 11521: 11520: 11480: 11479: 11430: 11429: 11424: 11388: 11387: 11361: 11353: 11052: 11050: 11049: 11044: 11032: 11030: 11029: 11024: 11022: 11010: 11008: 11007: 11002: 11000: 10988: 10986: 10985: 10980: 10972: 10960: 10958: 10957: 10952: 10941: 10927: 10915: 10913: 10912: 10907: 10905: 10904: 10869: 10867: 10866: 10861: 10859: 10858: 10809: 10807: 10806: 10801: 10796: 10772: 10770: 10769: 10764: 10728: 10726: 10725: 10720: 10715: 10697: 10695: 10694: 10689: 10687: 10675: 10673: 10672: 10667: 10662: 10641: 10639: 10638: 10633: 10588: 10586: 10585: 10580: 10568: 10566: 10565: 10560: 10524: 10522: 10521: 10516: 10514: 10475: 10473: 10472: 10467: 10455: 10453: 10452: 10447: 10435: 10433: 10432: 10427: 10415: 10413: 10412: 10407: 10396:with respect to 10395: 10393: 10392: 10387: 10369: 10367: 10366: 10361: 10349: 10347: 10346: 10341: 10329: 10327: 10326: 10321: 10316: 10315: 10295: 10293: 10292: 10287: 10247: 10246: 10201: 10200: 10179: 10177: 10176: 10171: 10157: 10156: 10129: 10128: 10083: 10081: 10080: 10075: 10020: 10019: 9974: 9973: 9955: 9953: 9952: 9947: 9926: 9924: 9923: 9918: 9900: 9898: 9897: 9892: 9869: 9868: 9849: 9847: 9846: 9841: 9829: 9827: 9826: 9821: 9819: 9818: 9802: 9800: 9799: 9794: 9782: 9780: 9779: 9774: 9772: 9771: 9755: 9753: 9752: 9747: 9720: 9718: 9717: 9712: 9701: 9700: 9675: 9673: 9672: 9667: 9640: 9638: 9637: 9632: 9621: 9620: 9595: 9593: 9592: 9587: 9569: 9567: 9566: 9561: 9550: 9549: 9516: 9515: 9490: 9488: 9487: 9482: 9448: 9446: 9445: 9440: 9429: 9428: 9398: 9397: 9375: 9373: 9372: 9367: 9356: 9355: 9337: 9317: 9316: 9304: 9290: 9288: 9287: 9282: 9261: 9259: 9258: 9253: 9236: 9235: 9216: 9214: 9213: 9208: 9196: 9194: 9193: 9188: 9176: 9174: 9173: 9168: 9156: 9154: 9153: 9148: 9136: 9134: 9133: 9128: 9116: 9114: 9113: 9108: 9096: 9094: 9093: 9088: 9083: 9082: 9064: 9063: 9047: 9045: 9044: 9039: 9019: 9017: 9016: 9011: 8999: 8997: 8996: 8991: 8986: 8985: 8966: 8964: 8963: 8958: 8946: 8944: 8943: 8938: 8926: 8924: 8923: 8918: 8900: 8898: 8897: 8892: 8881: 8878: 8869: 8867: 8866: 8861: 8850: 8847: 8838: 8836: 8835: 8830: 8828: 8827: 8811: 8809: 8808: 8803: 8801: 8800: 8784: 8782: 8781: 8776: 8771: 8770: 8751: 8749: 8748: 8743: 8725: 8723: 8722: 8717: 8705: 8703: 8702: 8697: 8677: 8675: 8674: 8669: 8658: 8655: 8641: 8638: 8633: 8632: 8614: 8612: 8611: 8606: 8582: 8580: 8579: 8574: 8554:, a subfield of 8549: 8547: 8546: 8541: 8529: 8527: 8526: 8521: 8509: 8507: 8506: 8501: 8499: 8498: 8482: 8480: 8479: 8474: 8472: 8471: 8455: 8453: 8452: 8447: 8435: 8433: 8432: 8427: 8415: 8413: 8412: 8407: 8396:of all elements 8391: 8389: 8388: 8383: 8369: 8368: 8341: 8340: 8297: 8295: 8294: 8289: 8277: 8275: 8274: 8269: 8257: 8255: 8254: 8249: 8237: 8235: 8234: 8229: 8227: 8226: 8201: 8199: 8198: 8193: 8167: 8166: 8145: 8144: 8128: 8126: 8125: 8120: 8108: 8106: 8105: 8100: 8088: 8086: 8085: 8080: 8062: 8060: 8059: 8054: 8040: 8039: 8008: 8006: 8005: 8000: 7998: 7997: 7953:the endofunctor 7641:coherent sheaves 7514:Hausdorff spaces 7458:homotopy classes 7456:, the space of 7433:trivial topology 7358:negative numbers 7260:Polynomial rings 7014:Ring extensions. 7005: 7003: 7002: 6997: 6929:Further examples 6506:diagonal functor 6387: 6385: 6384: 6379: 6374: 6373: 6343: 6341: 6340: 6335: 6333: 6332: 6301: 6299: 6298: 6293: 6285: 6278: 6277: 6257: 6243: 6239: 6238: 6221: 6203:the composition 6198: 6196: 6195: 6190: 6170: 6169: 6131: 6129: 6128: 6123: 6121: 6120: 6077: 6075: 6074: 6069: 6064: 6063: 6030: 6028: 6027: 6022: 6014: 6010: 6009: 5992: 5978: 5971: 5970: 5950: 5933:the composition 5928: 5926: 5925: 5920: 5900: 5899: 5877: 5875: 5874: 5869: 5772: 5770: 5769: 5764: 5744: 5743: 5711: 5709: 5708: 5703: 5698: 5697: 5661: 5659: 5658: 5653: 5633: 5632: 5579: 5577: 5576: 5571: 5551: 5550: 5514: 5512: 5511: 5506: 5486: 5485: 5319: 5317: 5316: 5311: 5294:was the functor 5210: 5208: 5207: 5202: 5151: 5149: 5148: 5143: 5141: 5140: 5117: 5115: 5114: 5109: 5107: 5106: 5090: 5088: 5087: 5082: 5080: 5079: 5066: 5064: 5063: 5058: 5056: 5055: 5054: 5033: 5031: 5030: 5025: 5023: 5019: 5018: 5000: 4999: 4977: 4976: 4957: 4956: 4938: 4937: 4918: 4917: 4872: 4870: 4869: 4864: 4862: 4836: 4835: 4800: 4799: 4762: 4760: 4759: 4754: 4736: 4734: 4733: 4728: 4646: 4644: 4643: 4638: 4633: 4618: 4607: 4592: 4579: 4577: 4576: 4571: 4566: 4551: 4540: 4525: 4495: 4493: 4492: 4487: 4485: 4472: 4471: 4470: 4446: 4445: 4444: 4372:consists of two 4323: 4319: 4260: 4239: 4217:category of sets 4210: 4196: 4182: 4119:for all objects 4115: 4113: 4112: 4107: 4087: 4086: 4081: 4048: 4047: 4042: 4027: 4026: 3997: 3995: 3994: 3989: 3969: 3968: 3963: 3930: 3929: 3924: 3893: 3865:consists of two 3837: 3835: 3834: 3829: 3817: 3815: 3814: 3809: 3797: 3795: 3794: 3789: 3777: 3775: 3774: 3769: 3754: 3752: 3751: 3746: 3730: 3728: 3727: 3722: 3710: 3708: 3707: 3702: 3690: 3688: 3687: 3682: 3680: 3653: 3651: 3650: 3645: 3637: 3636: 3635: 3619: 3618: 3578: 3576: 3575: 3570: 3546: 3544: 3543: 3538: 3515: 3513: 3512: 3507: 3499: 3498: 3467: 3465: 3464: 3459: 3426: 3424: 3423: 3418: 3385: 3383: 3382: 3377: 3365: 3363: 3362: 3357: 3345: 3343: 3342: 3337: 3305: 3304: 3288: 3286: 3285: 3280: 3268: 3266: 3265: 3260: 3239: 3237: 3236: 3231: 3219: 3217: 3216: 3211: 3199: 3197: 3196: 3191: 3179: 3177: 3176: 3171: 3155: 3153: 3152: 3147: 3135: 3133: 3132: 3127: 3111: 3109: 3108: 3103: 3076: 3074: 3073: 3068: 3052: 3050: 3049: 3044: 3032: 3030: 3029: 3024: 3012: 3010: 3009: 3004: 2996: 2975: 2973: 2972: 2967: 2965: 2964: 2963: 2917: 2916: 2900: 2898: 2897: 2892: 2868: 2866: 2865: 2860: 2830: 2828: 2827: 2822: 2799: 2798: 2782: 2780: 2779: 2774: 2741: 2739: 2738: 2733: 2700: 2698: 2697: 2692: 2680: 2678: 2677: 2672: 2660: 2658: 2657: 2652: 2620: 2619: 2603: 2601: 2600: 2595: 2583: 2581: 2580: 2575: 2554: 2552: 2551: 2546: 2534: 2532: 2531: 2526: 2514: 2512: 2511: 2506: 2494: 2492: 2491: 2486: 2470: 2468: 2467: 2462: 2450: 2448: 2447: 2442: 2426: 2424: 2423: 2418: 2233:The notion that 2094:to our problem: 1941:. The category 1906:if it defines a 1838: 1817: 1815: 1814: 1809: 1761: 1759: 1758: 1753: 1741: 1739: 1738: 1733: 1711: 1709: 1708: 1703: 1680:, we also write 1668: 1666: 1665: 1660: 1658: 1657: 1656: 1650: 1631: 1629: 1628: 1623: 1611: 1609: 1608: 1603: 1601: 1600: 1599: 1593: 1574: 1572: 1571: 1566: 1554: 1552: 1551: 1546: 1534: 1532: 1531: 1526: 1511: 1509: 1508: 1503: 1491: 1489: 1488: 1483: 1471: 1469: 1468: 1463: 1447: 1445: 1444: 1439: 1427: 1425: 1424: 1419: 1403: 1401: 1400: 1395: 1383: 1381: 1380: 1375: 1359: 1357: 1356: 1351: 1336: 1334: 1333: 1328: 1308: 1307: 1306: 1300: 1281: 1279: 1278: 1273: 1260: 1258: 1257: 1252: 1240: 1238: 1237: 1232: 1214: 1212: 1211: 1206: 1191: 1189: 1188: 1183: 1163: 1162: 1161: 1155: 1122: 1121: 1120: 1114: 1099: 1098: 1044: 1042: 1041: 1036: 1034: 1033: 1020: 1018: 1017: 1012: 1010: 1009: 992: 990: 989: 984: 982: 981: 968: 966: 965: 960: 958: 957: 941: 939: 938: 933: 914: 912: 911: 906: 888: 886: 885: 880: 867: 865: 864: 859: 848:left adjoint to 841: 839: 838: 833: 818: 816: 815: 810: 808: 807: 794: 792: 791: 786: 774: 772: 771: 766: 764: 750: 749: 722: 721: 708: 706: 705: 700: 698: 684: 683: 656: 655: 642: 640: 639: 634: 632: 631: 618: 616: 615: 610: 598: 596: 595: 590: 588: 587: 586: 583: 567: 566: 539: 538: 525: 523: 522: 517: 515: 514: 513: 510: 494: 493: 466: 465: 452: 450: 449: 444: 432: 430: 429: 424: 405: 403: 402: 397: 377: 376: 375: 369: 336: 335: 334: 328: 302: 300: 299: 294: 292: 291: 278: 276: 275: 270: 258: 256: 255: 250: 248: 247: 234: 232: 231: 226: 211: 209: 208: 203: 201: 200: 191: 190: 171: 169: 168: 163: 161: 160: 151: 150: 124: 122: 121: 116: 114: 113: 100: 98: 97: 92: 90: 89: 50:, one being the 48:adjoint functors 25:Adjunction space 16910: 16909: 16905: 16904: 16903: 16901: 16900: 16899: 16885: 16884: 16883: 16878: 16800: 16794: 16764: 16759: 16713: 16683: 16650: 16627: 16618: 16575: 16559: 16510: 16500: 16487: 16470: 16419: 16357: 16326:Initial objects 16312: 16258: 16151: 16140: 16138:Category theory 16135: 16077:of The Catsters 16065: 16061: 16043: 16007: 15996: 15986: 15981: 15980: 15958: 15954: 15941: 15940: 15936: 15916: 15912: 15896:10.2307/1993102 15878: 15872: 15868: 15851: 15847: 15842: 15771: 15767: 15759: 15756: 15755: 15725: 15724: 15720: 15712: 15709: 15708: 15677: 15676: 15667: 15666: 15658: 15655: 15654: 15628: 15613: 15592: 15585: 15570: 15548: 15541: 15523: 15488: 15428: 15423: 15348: 15347: 15336: 15335: 15307: 15306: 15295: 15294: 15279: 15275: 15273: 15270: 15269: 15219: 15154: 15117: 15116: 15106: 15105: 15101: 15089: 15069: 15060: 15049: 15041: 15034: 15033: 15025: 15011: 15000: 14989: 14983: 14975: 14967: 14956: 14950: 14943: 14942: 14938: 14933: 14931: 14928: 14927: 14873: 14871: 14868: 14867: 14830: 14822: 14819: 14818: 14780: 14759: 14756: 14755: 14739: 14736: 14735: 14718: 14717: 14702: 14698: 14686: 14682: 14666: 14658: 14655: 14654: 14626: 14618: 14614: 14612: 14609: 14608: 14537:Conversely, if 14502:If the functor 14500: 14442: 14439: 14438: 14417: 14399: 14390: 14335: 14322: 14305: 14248: 14242: 14237: 14211: 14207: 14195: 14191: 14173: 14169: 14167: 14164: 14163: 14155: 14149: 14143: 14110: 14106: 14088: 14084: 14072: 14068: 14066: 14063: 14062: 14052: 14046: 14036: 13979: 13978: 13957: 13953: 13932: 13921: 13914: 13913: 13907: 13903: 13864: 13860: 13856: 13854: 13851: 13850: 13829: 13807: 13758: 13747: 13746: 13734: 13730: 13728: 13725: 13724: 13678: 13667: 13666: 13651: 13647: 13629: 13625: 13616: 13612: 13610: 13607: 13606: 13565: 13554: 13553: 13541: 13537: 13535: 13532: 13531: 13485: 13474: 13473: 13458: 13454: 13442: 13428: 13415: 13411: 13409: 13406: 13405: 13357: 13354: 13353: 13344: 13334: 13305:Given functors 13303: 13281: 13280: 13259: 13255: 13246: 13245: 13230: 13226: 13214: 13210: 13195: 13194: 13188: 13184: 13154: 13150: 13137: 13124: 13122: 13119: 13118: 13112: 13102: 13092: 13063: 13062: 13047: 13043: 13028: 13027: 13018: 13014: 12996: 12992: 12977: 12976: 12967: 12963: 12930: 12926: 12919: 12906: 12904: 12901: 12900: 12894: 12882: 12876: 12847: 12846: 12825: 12821: 12797: 12793: 12790: 12789: 12783: 12779: 12740: 12736: 12732: 12730: 12727: 12726: 12688: 12678: 12655: 12652: 12651: 12623:Given functors 12621: 12596: 12595: 12588: 12562: 12561: 12530: 12529: 12471: 12470: 12463: 12455: 12448: 12437: 12430: 12415: 12408: 12397: 12390: 12376: 12342: 12332: 12322: 12285: 12275: 12239: 12226: 12215: 12196: 12195: 12181: 12180: 12172: 12171: 12163: 12152: 12145: 12111: 12097: 12043: 12009: 11981: 11955: 11954: 11945: 11941: 11929: 11925: 11912: 11903: 11899: 11896: 11895: 11886: 11882: 11864: 11860: 11853: 11844: 11840: 11836: 11834: 11831: 11830: 11808: 11807: 11774: 11763: 11762: 11758: 11753: 11747: 11743: 11736: 11724: 11720: 11702: 11698: 11695: 11694: 11661: 11650: 11649: 11645: 11640: 11634: 11630: 11623: 11611: 11607: 11595: 11581: 11574: 11573: 11543: 11532: 11531: 11527: 11522: 11516: 11512: 11490: 11469: 11465: 11456: 11455: 11425: 11414: 11413: 11409: 11404: 11383: 11379: 11372: 11354: 11343: 11329: 11327: 11324: 11323: 11280: 11234: 11171: 11159: 11138: 11128: 11059: 11038: 11035: 11034: 11018: 11016: 11013: 11012: 10996: 10994: 10991: 10990: 10968: 10966: 10963: 10962: 10937: 10923: 10921: 10918: 10917: 10900: 10896: 10882: 10879: 10878: 10851: 10847: 10815: 10812: 10811: 10792: 10778: 10775: 10774: 10734: 10731: 10730: 10711: 10703: 10700: 10699: 10683: 10681: 10678: 10677: 10658: 10650: 10647: 10646: 10594: 10591: 10590: 10574: 10571: 10570: 10530: 10527: 10526: 10510: 10508: 10505: 10504: 10494: 10461: 10458: 10457: 10456:is replaced by 10441: 10438: 10437: 10421: 10418: 10417: 10401: 10398: 10397: 10375: 10372: 10371: 10355: 10352: 10351: 10335: 10332: 10331: 10311: 10307: 10305: 10302: 10301: 10239: 10235: 10196: 10192: 10190: 10187: 10186: 10152: 10148: 10124: 10120: 10093: 10090: 10089: 10012: 10008: 9969: 9965: 9963: 9960: 9959: 9932: 9929: 9928: 9906: 9903: 9902: 9861: 9857: 9855: 9852: 9851: 9835: 9832: 9831: 9814: 9810: 9808: 9805: 9804: 9788: 9785: 9784: 9767: 9763: 9761: 9758: 9757: 9726: 9723: 9722: 9693: 9689: 9681: 9678: 9677: 9646: 9643: 9642: 9641:, then clearly 9613: 9609: 9601: 9598: 9597: 9575: 9572: 9571: 9542: 9538: 9508: 9504: 9496: 9493: 9492: 9461: 9458: 9457: 9421: 9417: 9393: 9389: 9387: 9384: 9383: 9351: 9347: 9333: 9312: 9308: 9300: 9298: 9295: 9294: 9270: 9267: 9266: 9228: 9224: 9222: 9219: 9218: 9202: 9199: 9198: 9182: 9179: 9178: 9162: 9159: 9158: 9142: 9139: 9138: 9122: 9119: 9118: 9102: 9099: 9098: 9078: 9074: 9059: 9055: 9053: 9050: 9049: 9033: 9030: 9029: 9005: 9002: 9001: 8981: 8977: 8972: 8969: 8968: 8952: 8949: 8948: 8932: 8929: 8928: 8906: 8903: 8902: 8877: 8875: 8872: 8871: 8846: 8844: 8841: 8840: 8823: 8819: 8817: 8814: 8813: 8796: 8792: 8790: 8787: 8786: 8766: 8762: 8757: 8754: 8753: 8731: 8728: 8727: 8711: 8708: 8707: 8691: 8688: 8687: 8654: 8637: 8628: 8624: 8622: 8619: 8618: 8588: 8585: 8584: 8568: 8565: 8564: 8535: 8532: 8531: 8515: 8512: 8511: 8494: 8490: 8488: 8485: 8484: 8467: 8463: 8461: 8458: 8457: 8456:to which it is 8441: 8438: 8437: 8421: 8418: 8417: 8401: 8398: 8397: 8364: 8360: 8336: 8332: 8305: 8302: 8301: 8283: 8280: 8279: 8263: 8260: 8259: 8243: 8240: 8239: 8222: 8218: 8216: 8213: 8212: 8162: 8158: 8140: 8136: 8134: 8131: 8130: 8114: 8111: 8110: 8094: 8091: 8090: 8068: 8065: 8064: 8035: 8031: 8014: 8011: 8010: 7993: 7989: 7987: 7984: 7983: 7980:Quantification. 7976: 7922: 7871: 7869:Category theory 7802:is a subset of 7748:William Lawvere 7686:if and only if 7672: 7649:The article on 7647:Soberification. 7638: 7591: 7497:homotopy theory 7419:, creating the 7393: 7282:polynomial ring 7275: 7268: 7251: 7240: 7166: 7101:Tensor products 6991: 6988: 6987: 6958:and defining a 6936: 6931: 6870: 6863: 6820: 6813: 6765: 6700: 6692: 6685: 6679: 6670: 6661: 6652: 6645: 6634: 6627: 6620: 6613: 6606: 6599: 6551: 6544: 6537: 6530: 6496: 6489: 6481: 6475: 6440:fibred products 6433: 6414: 6369: 6365: 6357: 6354: 6353: 6325: 6321: 6319: 6316: 6315: 6273: 6269: 6256: 6231: 6227: 6220: 6212: 6209: 6208: 6165: 6161: 6159: 6156: 6155: 6113: 6109: 6107: 6104: 6103: 6059: 6055: 6047: 6044: 6043: 6002: 5998: 5991: 5966: 5962: 5949: 5941: 5938: 5937: 5895: 5891: 5889: 5886: 5885: 5839: 5836: 5835: 5739: 5735: 5733: 5730: 5729: 5693: 5689: 5675: 5672: 5671: 5628: 5624: 5622: 5619: 5618: 5601:For each group 5546: 5542: 5540: 5537: 5536: 5481: 5477: 5475: 5472: 5471: 5383: 5378: 5320:(i.e. take the 5299: 5296: 5295: 5244: 5184: 5181: 5180: 5177:string diagrams 5133: 5129: 5127: 5124: 5123: 5122:to itself, and 5102: 5098: 5096: 5093: 5092: 5075: 5074: 5072: 5069: 5068: 5050: 5049: 5045: 5043: 5040: 5039: 5021: 5020: 5011: 5007: 4995: 4991: 4978: 4969: 4965: 4962: 4961: 4952: 4948: 4930: 4926: 4919: 4910: 4906: 4902: 4900: 4897: 4896: 4860: 4859: 4837: 4831: 4827: 4824: 4823: 4801: 4795: 4791: 4787: 4785: 4782: 4781: 4742: 4739: 4738: 4698: 4695: 4694: 4661: 4655: 4617: 4591: 4586: 4583: 4582: 4550: 4524: 4519: 4516: 4515: 4483: 4482: 4466: 4465: 4461: 4454: 4448: 4447: 4440: 4439: 4435: 4419: 4412: 4410: 4407: 4406: 4358: 4335: 4303: 4291: 4276:Naturality of Ξ¦ 4245: 4227: 4202: 4190: 4184: 4176: 4170: 4082: 4071: 4070: 4043: 4032: 4031: 4016: 4012: 4010: 4007: 4006: 3964: 3953: 3952: 3925: 3914: 3913: 3905: 3902: 3901: 3881: 3848: 3823: 3820: 3819: 3803: 3800: 3799: 3798:if and only if 3783: 3780: 3779: 3763: 3760: 3759: 3740: 3737: 3736: 3716: 3713: 3712: 3696: 3693: 3692: 3673: 3659: 3656: 3655: 3628: 3627: 3623: 3614: 3610: 3584: 3581: 3580: 3552: 3549: 3548: 3532: 3529: 3528: 3494: 3490: 3473: 3470: 3469: 3432: 3429: 3428: 3391: 3388: 3387: 3371: 3368: 3367: 3351: 3348: 3347: 3300: 3296: 3294: 3291: 3290: 3289:and a morphism 3274: 3271: 3270: 3245: 3242: 3241: 3225: 3222: 3221: 3205: 3202: 3201: 3185: 3182: 3181: 3165: 3162: 3161: 3141: 3138: 3137: 3121: 3118: 3117: 3085: 3082: 3081: 3062: 3059: 3058: 3038: 3035: 3034: 3018: 3015: 3014: 2989: 2981: 2978: 2977: 2956: 2955: 2951: 2912: 2908: 2906: 2903: 2902: 2874: 2871: 2870: 2854: 2851: 2850: 2794: 2790: 2788: 2785: 2784: 2747: 2744: 2743: 2706: 2703: 2702: 2686: 2683: 2682: 2666: 2663: 2662: 2615: 2611: 2609: 2606: 2605: 2604:and a morphism 2589: 2586: 2585: 2560: 2557: 2556: 2540: 2537: 2536: 2520: 2517: 2516: 2500: 2497: 2496: 2480: 2477: 2476: 2471:there exists a 2456: 2453: 2452: 2436: 2433: 2432: 2400: 2397: 2396: 2393: 2310: 2282: 2216: 2145:adjoint functor 2107: 2100: 2093: 2086: 2079: 2068: 2049: 2045: 2041: 2034: 2027: 2016: 2001: 1990: 1853: 1845:colimits/limits 1839: 1831: 1824: 1767: 1764: 1763: 1747: 1744: 1743: 1727: 1724: 1723: 1688: 1685: 1684: 1652: 1651: 1640: 1639: 1637: 1634: 1633: 1617: 1614: 1613: 1595: 1594: 1583: 1582: 1580: 1577: 1576: 1560: 1557: 1556: 1540: 1537: 1536: 1520: 1517: 1516: 1497: 1494: 1493: 1477: 1474: 1473: 1457: 1454: 1453: 1433: 1430: 1429: 1413: 1410: 1409: 1389: 1386: 1385: 1369: 1366: 1365: 1342: 1339: 1338: 1302: 1301: 1290: 1289: 1287: 1284: 1283: 1282:is an arrow in 1267: 1264: 1263: 1246: 1243: 1242: 1226: 1223: 1222: 1200: 1197: 1196: 1157: 1156: 1145: 1144: 1116: 1115: 1104: 1103: 1091: 1087: 1085: 1082: 1081: 1051: 1029: 1028: 1026: 1023: 1022: 1005: 1004: 1002: 999: 998: 977: 976: 974: 971: 970: 953: 952: 950: 947: 946: 921: 918: 917: 900: 897: 896: 874: 871: 870: 853: 850: 849: 827: 824: 823: 803: 802: 800: 797: 796: 780: 777: 776: 754: 745: 744: 717: 716: 714: 711: 710: 688: 679: 678: 651: 650: 648: 645: 644: 627: 626: 624: 621: 620: 604: 601: 600: 582: 578: 571: 562: 561: 534: 533: 531: 528: 527: 509: 505: 498: 489: 488: 461: 460: 458: 455: 454: 438: 435: 434: 418: 415: 414: 371: 370: 359: 358: 330: 329: 318: 317: 315: 312: 311: 287: 286: 284: 281: 280: 264: 261: 260: 243: 242: 240: 237: 236: 220: 217: 216: 196: 195: 186: 185: 177: 174: 173: 156: 155: 146: 145: 137: 134: 133: 109: 108: 106: 103: 102: 85: 84: 82: 79: 78: 36:category theory 34:, specifically 28: 17: 12: 11: 5: 16908: 16898: 16897: 16880: 16879: 16877: 16876: 16871: 16866: 16861: 16856: 16851: 16846: 16841: 16836: 16831: 16826: 16821: 16816: 16811: 16805: 16802: 16801: 16793: 16792: 16785: 16778: 16770: 16761: 16760: 16758: 16757: 16747: 16737: 16726: 16723: 16722: 16719: 16718: 16715: 16714: 16712: 16711: 16706: 16701: 16687: 16681: 16676: 16671: 16665: 16663: 16656: 16655: 16652: 16651: 16649: 16648: 16643: 16632: 16630: 16625: 16620: 16619: 16617: 16616: 16611: 16606: 16601: 16596: 16591: 16580: 16578: 16573: 16565: 16561: 16560: 16558: 16553: 16551:String diagram 16548: 16543: 16541:Model category 16538: 16533: 16528: 16523: 16518: 16516: 16509: 16508: 16505: 16502: 16501: 16489: 16488: 16481: 16479: 16476: 16475: 16472: 16471: 16469: 16468: 16463: 16461:Comma category 16458: 16453: 16448: 16443: 16438: 16433: 16427: 16425: 16421: 16420: 16418: 16417: 16407: 16397: 16395:Abelian groups 16392: 16387: 16382: 16377: 16371: 16369: 16363: 16362: 16359: 16358: 16356: 16355: 16350: 16345: 16344: 16343: 16333: 16328: 16322: 16320: 16314: 16313: 16311: 16310: 16305: 16300: 16299: 16298: 16288: 16283: 16277: 16275: 16266: 16260: 16259: 16257: 16256: 16251: 16246: 16241: 16236: 16231: 16226: 16221: 16216: 16211: 16206: 16201: 16200: 16199: 16194: 16189: 16184: 16179: 16174: 16163: 16161: 16153: 16152: 16142: 16141: 16134: 16133: 16126: 16119: 16111: 16105: 16104: 16091:, categories, 16078: 16060: 16059:External links 16057: 16056: 16055: 16041: 16019: 16005: 15985: 15982: 15979: 15978: 15952: 15934: 15910: 15889:(2): 294–329. 15866: 15844: 15843: 15841: 15838: 15795: 15794: 15782: 15779: 15774: 15770: 15766: 15763: 15749: 15748: 15737: 15734: 15728: 15723: 15719: 15716: 15694: 15693: 15680: 15675: 15670: 15665: 15662: 15650:. The functor 15627: 15624: 15609: 15590: 15583: 15566: 15546: 15537: 15521: 15487: 15484: 15427: 15424: 15422: 15419: 15384: 15383: 15372: 15369: 15366: 15363: 15360: 15357: 15351: 15345: 15342: 15339: 15334: 15331: 15328: 15325: 15322: 15319: 15316: 15310: 15304: 15301: 15298: 15293: 15288: 15285: 15282: 15278: 15218: 15215: 15214: 15213: 15206: 15199: 15192: 15153: 15150: 15131: 15130: 15115: 15109: 15104: 15097: 15093: 15088: 15085: 15079: 15075: 15072: 15068: 15064: 15059: 15055: 15052: 15047: 15044: 15040: 15037: 15035: 15031: 15028: 15024: 15021: 15017: 15014: 15006: 15003: 14999: 14995: 14992: 14987: 14981: 14978: 14973: 14970: 14962: 14959: 14954: 14946: 14941: 14937: 14935: 14913: 14912: 14901: 14898: 14895: 14892: 14889: 14886: 14883: 14879: 14876: 14861: 14860: 14849: 14846: 14843: 14840: 14836: 14833: 14829: 14826: 14779: 14776: 14763: 14743: 14732: 14731: 14716: 14713: 14708: 14705: 14701: 14697: 14692: 14689: 14685: 14681: 14678: 14675: 14672: 14669: 14667: 14664: 14661: 14657: 14656: 14653: 14650: 14647: 14644: 14641: 14638: 14635: 14632: 14629: 14627: 14624: 14621: 14617: 14616: 14594: 14593: 14582: 14499: 14496: 14495: 14494: 14481: 14458: 14455: 14452: 14449: 14446: 14428: 14427: 14413: 14392: 14391: 14386: 14365: 14364: 14325: 14324: 14318: 14301: 14276:Peter J. Freyd 14241: 14238: 14236: 14233: 14232: 14231: 14217: 14214: 14210: 14206: 14203: 14198: 14194: 14190: 14187: 14184: 14179: 14176: 14172: 14161: 14151: 14145: 14141: 14130: 14118: 14113: 14109: 14105: 14102: 14099: 14094: 14091: 14087: 14083: 14078: 14075: 14071: 14059: 14058: 14048: 14038: 14032: 14020: 14019: 13992: 13977: 13974: 13971: 13968: 13965: 13960: 13956: 13952: 13949: 13946: 13943: 13938: 13935: 13930: 13927: 13924: 13920: 13916: 13915: 13910: 13906: 13902: 13899: 13896: 13893: 13890: 13887: 13884: 13881: 13878: 13873: 13870: 13867: 13863: 13859: 13858: 13847: 13846: 13843: 13825: 13803: 13796: 13784: 13781: 13778: 13775: 13772: 13769: 13766: 13761: 13756: 13753: 13750: 13745: 13740: 13737: 13733: 13723:, where   13704: 13701: 13698: 13695: 13692: 13689: 13686: 13681: 13676: 13673: 13670: 13665: 13662: 13657: 13654: 13650: 13646: 13641: 13638: 13635: 13632: 13628: 13624: 13619: 13615: 13603: 13591: 13588: 13585: 13582: 13579: 13576: 13573: 13568: 13563: 13560: 13557: 13552: 13547: 13544: 13540: 13530:, where   13511: 13508: 13505: 13502: 13499: 13496: 13493: 13488: 13483: 13480: 13477: 13472: 13469: 13464: 13461: 13457: 13453: 13448: 13445: 13440: 13437: 13434: 13431: 13427: 13423: 13418: 13414: 13398: 13397: 13385: 13382: 13379: 13376: 13373: 13370: 13367: 13364: 13361: 13340: 13330: 13302: 13299: 13298: 13297: 13294: 13279: 13276: 13273: 13270: 13265: 13262: 13258: 13254: 13251: 13249: 13247: 13244: 13241: 13236: 13233: 13229: 13225: 13222: 13217: 13213: 13209: 13206: 13203: 13200: 13198: 13196: 13191: 13187: 13183: 13180: 13177: 13174: 13171: 13168: 13165: 13162: 13157: 13153: 13149: 13146: 13143: 13140: 13138: 13136: 13133: 13130: 13127: 13126: 13115: 13114: 13108: 13098: 13088: 13080: 13079: 13076: 13061: 13058: 13053: 13050: 13046: 13042: 13039: 13036: 13033: 13031: 13029: 13026: 13021: 13017: 13013: 13010: 13007: 13002: 12999: 12995: 12991: 12988: 12985: 12982: 12980: 12978: 12975: 12970: 12966: 12962: 12959: 12956: 12953: 12950: 12947: 12944: 12941: 12938: 12933: 12929: 12925: 12922: 12920: 12918: 12915: 12912: 12909: 12908: 12897: 12896: 12890: 12878: 12872: 12864: 12863: 12860: 12845: 12842: 12839: 12836: 12833: 12828: 12824: 12820: 12817: 12814: 12811: 12806: 12803: 12800: 12796: 12792: 12791: 12786: 12782: 12778: 12775: 12772: 12769: 12766: 12763: 12760: 12757: 12754: 12749: 12746: 12743: 12739: 12735: 12734: 12723: 12722: 12684: 12674: 12659: 12620: 12617: 12612: 12611: 12610: 12609: 12593: 12586: 12582: 12559: 12555: 12527: 12523: 12468: 12461: 12457: 12453: 12446: 12435: 12428: 12413: 12406: 12402:, any objects 12395: 12388: 12378: 12372: 12334: 12324: 12318: 12301:, each object 12281: 12271: 12268: 12267: 12266: 12255: 12235: 12232: 12224: 12213: 12193: 12189: 12178: 12174: 12169: 12165: 12161: 12150: 12143: 12133: 12107: 12093: 12042: 12039: 12027: 12026: 12005: 11998: 11977: 11969: 11968: 11951: 11948: 11944: 11940: 11937: 11932: 11928: 11924: 11921: 11918: 11915: 11913: 11909: 11906: 11902: 11898: 11897: 11894: 11889: 11885: 11881: 11878: 11875: 11870: 11867: 11863: 11859: 11856: 11854: 11850: 11847: 11843: 11839: 11838: 11827: 11826: 11822: 11821: 11806: 11803: 11800: 11797: 11794: 11791: 11788: 11785: 11782: 11777: 11772: 11769: 11766: 11759: 11757: 11754: 11750: 11746: 11742: 11739: 11737: 11735: 11730: 11727: 11723: 11719: 11714: 11711: 11708: 11705: 11701: 11697: 11696: 11693: 11690: 11687: 11684: 11681: 11678: 11675: 11672: 11669: 11664: 11659: 11656: 11653: 11646: 11644: 11641: 11637: 11633: 11629: 11626: 11624: 11622: 11617: 11614: 11610: 11606: 11601: 11598: 11593: 11590: 11587: 11584: 11580: 11576: 11575: 11572: 11569: 11566: 11563: 11560: 11557: 11554: 11551: 11546: 11541: 11538: 11535: 11528: 11526: 11523: 11519: 11515: 11511: 11508: 11505: 11502: 11499: 11496: 11493: 11491: 11489: 11486: 11483: 11478: 11475: 11472: 11468: 11464: 11461: 11458: 11457: 11454: 11451: 11448: 11445: 11442: 11439: 11436: 11433: 11428: 11423: 11420: 11417: 11410: 11408: 11405: 11403: 11400: 11397: 11394: 11391: 11386: 11382: 11378: 11375: 11373: 11371: 11368: 11365: 11360: 11357: 11352: 11349: 11346: 11342: 11338: 11335: 11332: 11331: 11320: 11319: 11305: 11304: 11303: 11302: 11272: 11226: 11181: 11180: 11167: 11164: 11155: 11144: 11134: 11124: 11117: 11099: 11058: 11055: 11042: 11021: 10999: 10978: 10975: 10971: 10950: 10947: 10944: 10940: 10936: 10933: 10930: 10926: 10903: 10899: 10895: 10892: 10889: 10886: 10857: 10854: 10850: 10846: 10843: 10840: 10837: 10834: 10831: 10828: 10825: 10822: 10819: 10799: 10795: 10791: 10788: 10785: 10782: 10762: 10759: 10756: 10753: 10750: 10747: 10744: 10741: 10738: 10718: 10714: 10710: 10707: 10686: 10665: 10661: 10657: 10654: 10631: 10628: 10625: 10622: 10619: 10616: 10613: 10610: 10607: 10604: 10601: 10598: 10578: 10558: 10555: 10552: 10549: 10546: 10543: 10540: 10537: 10534: 10513: 10493: 10490: 10489: 10488: 10478: 10477: 10465: 10445: 10425: 10405: 10385: 10382: 10379: 10359: 10339: 10319: 10314: 10310: 10298: 10297: 10296: 10285: 10282: 10278: 10275: 10272: 10268: 10265: 10262: 10259: 10256: 10253: 10250: 10245: 10242: 10238: 10234: 10231: 10228: 10225: 10222: 10219: 10216: 10213: 10210: 10207: 10204: 10199: 10195: 10181: 10169: 10166: 10163: 10160: 10155: 10151: 10147: 10144: 10141: 10138: 10135: 10132: 10127: 10123: 10118: 10115: 10112: 10109: 10106: 10103: 10100: 10097: 10086: 10085: 10084: 10073: 10070: 10067: 10064: 10061: 10058: 10055: 10051: 10048: 10045: 10041: 10038: 10035: 10032: 10029: 10026: 10023: 10018: 10015: 10011: 10007: 10004: 10001: 9998: 9995: 9992: 9989: 9986: 9983: 9980: 9977: 9972: 9968: 9945: 9942: 9939: 9936: 9916: 9913: 9910: 9890: 9887: 9884: 9881: 9878: 9875: 9872: 9867: 9864: 9860: 9850:'s, such that 9839: 9817: 9813: 9792: 9770: 9766: 9745: 9742: 9739: 9736: 9733: 9730: 9710: 9707: 9704: 9699: 9696: 9692: 9688: 9685: 9665: 9662: 9659: 9656: 9653: 9650: 9630: 9627: 9624: 9619: 9616: 9612: 9608: 9605: 9585: 9582: 9579: 9559: 9556: 9553: 9548: 9545: 9541: 9537: 9534: 9531: 9528: 9525: 9522: 9519: 9514: 9511: 9507: 9503: 9500: 9480: 9477: 9474: 9471: 9468: 9465: 9453: 9452: 9451: 9450: 9438: 9435: 9432: 9427: 9424: 9420: 9416: 9413: 9410: 9407: 9404: 9401: 9396: 9392: 9378: 9377: 9376: 9365: 9362: 9359: 9354: 9350: 9346: 9343: 9340: 9336: 9332: 9329: 9326: 9323: 9320: 9315: 9311: 9307: 9303: 9280: 9277: 9274: 9263: 9251: 9248: 9245: 9242: 9239: 9234: 9231: 9227: 9206: 9186: 9166: 9146: 9126: 9106: 9086: 9081: 9077: 9073: 9070: 9067: 9062: 9058: 9037: 9022: 9021: 9009: 8989: 8984: 8980: 8976: 8956: 8936: 8916: 8913: 8910: 8890: 8887: 8884: 8859: 8856: 8853: 8826: 8822: 8799: 8795: 8774: 8769: 8765: 8761: 8741: 8738: 8735: 8715: 8695: 8680: 8679: 8678: 8667: 8664: 8661: 8653: 8650: 8647: 8644: 8636: 8631: 8627: 8604: 8601: 8598: 8595: 8592: 8572: 8560: 8559: 8539: 8519: 8497: 8493: 8470: 8466: 8445: 8425: 8405: 8394: 8393: 8392: 8381: 8378: 8375: 8372: 8367: 8363: 8359: 8356: 8353: 8350: 8347: 8344: 8339: 8335: 8330: 8327: 8324: 8321: 8318: 8315: 8312: 8309: 8287: 8267: 8247: 8225: 8221: 8204: 8203: 8191: 8188: 8185: 8182: 8179: 8176: 8173: 8170: 8165: 8161: 8157: 8154: 8151: 8148: 8143: 8139: 8118: 8098: 8078: 8075: 8072: 8052: 8049: 8046: 8043: 8038: 8034: 8030: 8027: 8024: 8021: 8018: 7996: 7992: 7975: 7972: 7971: 7970: 7944: 7920: 7914: 7870: 7867: 7866: 7865: 7860:is adjoint to 7846:ideal quotient 7831: 7744: 7733: 7671: 7668: 7667: 7666: 7644: 7636: 7589: 7568:continuous map 7561: 7500: 7440: 7421:discrete space 7392: 7389: 7388: 7387: 7373: 7338:vector bundles 7327: 7312:abelianization 7288:Abelianization 7285: 7273: 7266: 7257: 7249: 7238: 7229: 7207:group of units 7184: 7162: 7137:. The functor 7109:is a ring and 7097: 7046:tensor product 7011: 6995: 6982:disjoint union 6980:by taking the 6963: 6935: 6932: 6930: 6927: 6926: 6925: 6905: 6904: 6868: 6861: 6818: 6811: 6764: 6761: 6760: 6759: 6754: 6753: 6696: 6690: 6683: 6675: 6666: 6657: 6650: 6643: 6632: 6625: 6618: 6611: 6604: 6597: 6583: 6582: 6566: 6565: 6549: 6542: 6535: 6528: 6494: 6487: 6479: 6473: 6432: 6429: 6413: 6410: 6377: 6372: 6368: 6364: 6361: 6331: 6328: 6324: 6304: 6303: 6291: 6288: 6281: 6276: 6272: 6268: 6265: 6260: 6255: 6252: 6249: 6246: 6237: 6234: 6230: 6224: 6219: 6216: 6188: 6185: 6182: 6179: 6176: 6173: 6168: 6164: 6119: 6116: 6112: 6067: 6062: 6058: 6054: 6051: 6032: 6031: 6020: 6017: 6008: 6005: 6001: 5995: 5990: 5987: 5984: 5981: 5974: 5969: 5965: 5961: 5958: 5953: 5948: 5945: 5918: 5915: 5912: 5909: 5906: 5903: 5898: 5894: 5867: 5864: 5861: 5858: 5855: 5852: 5849: 5846: 5843: 5762: 5759: 5756: 5753: 5750: 5747: 5742: 5738: 5701: 5696: 5692: 5688: 5685: 5682: 5679: 5651: 5648: 5645: 5642: 5639: 5636: 5631: 5627: 5569: 5566: 5563: 5560: 5557: 5554: 5549: 5545: 5531:of some group 5504: 5501: 5498: 5495: 5492: 5489: 5484: 5480: 5382: 5379: 5377: 5374: 5322:tensor product 5309: 5306: 5303: 5288:abelian groups 5284: 5283: 5243: 5240: 5200: 5197: 5194: 5191: 5188: 5139: 5136: 5132: 5105: 5101: 5078: 5053: 5048: 5036: 5035: 5017: 5014: 5010: 5006: 5003: 4998: 4994: 4990: 4987: 4984: 4981: 4979: 4975: 4972: 4968: 4964: 4963: 4960: 4955: 4951: 4947: 4944: 4941: 4936: 4933: 4929: 4925: 4922: 4920: 4916: 4913: 4909: 4905: 4904: 4874: 4873: 4858: 4855: 4852: 4849: 4846: 4843: 4840: 4838: 4834: 4830: 4826: 4825: 4822: 4819: 4816: 4813: 4810: 4807: 4804: 4802: 4798: 4794: 4790: 4789: 4752: 4749: 4746: 4726: 4723: 4720: 4717: 4714: 4711: 4708: 4705: 4702: 4670:respectively. 4657: 4651: 4648: 4647: 4636: 4629: 4626: 4621: 4616: 4613: 4610: 4603: 4600: 4595: 4590: 4580: 4569: 4562: 4559: 4554: 4549: 4546: 4543: 4536: 4533: 4528: 4523: 4497: 4496: 4481: 4478: 4475: 4469: 4464: 4460: 4457: 4455: 4453: 4450: 4449: 4443: 4438: 4434: 4431: 4428: 4425: 4422: 4420: 4418: 4415: 4414: 4357: 4354: 4352:) is similar. 4333: 4312:) is given by 4301: 4289: 4186: 4172: 4117: 4116: 4105: 4102: 4099: 4096: 4093: 4090: 4085: 4080: 4077: 4074: 4069: 4066: 4063: 4060: 4057: 4054: 4051: 4046: 4041: 4038: 4035: 4030: 4025: 4022: 4019: 4015: 4000: 3999: 3987: 3984: 3981: 3978: 3975: 3972: 3967: 3962: 3959: 3956: 3951: 3948: 3945: 3942: 3939: 3936: 3933: 3928: 3923: 3920: 3917: 3912: 3909: 3847: 3844: 3827: 3807: 3787: 3767: 3744: 3720: 3700: 3691:a morphism in 3679: 3676: 3672: 3669: 3666: 3663: 3643: 3640: 3634: 3631: 3626: 3622: 3617: 3613: 3609: 3606: 3603: 3600: 3597: 3594: 3591: 3588: 3568: 3565: 3562: 3559: 3556: 3536: 3505: 3502: 3497: 3493: 3489: 3486: 3483: 3480: 3477: 3457: 3454: 3451: 3448: 3445: 3442: 3439: 3436: 3416: 3413: 3410: 3407: 3404: 3401: 3398: 3395: 3375: 3355: 3335: 3332: 3329: 3326: 3323: 3320: 3317: 3314: 3311: 3308: 3303: 3299: 3278: 3258: 3255: 3252: 3249: 3229: 3209: 3189: 3169: 3145: 3125: 3101: 3098: 3095: 3092: 3089: 3066: 3042: 3022: 3002: 2999: 2995: 2992: 2988: 2985: 2962: 2959: 2954: 2950: 2947: 2944: 2941: 2938: 2935: 2932: 2929: 2926: 2923: 2920: 2915: 2911: 2890: 2887: 2884: 2881: 2878: 2858: 2820: 2817: 2814: 2811: 2808: 2805: 2802: 2797: 2793: 2772: 2769: 2766: 2763: 2760: 2757: 2754: 2751: 2731: 2728: 2725: 2722: 2719: 2716: 2713: 2710: 2690: 2670: 2650: 2647: 2644: 2641: 2638: 2635: 2632: 2629: 2626: 2623: 2618: 2614: 2593: 2573: 2570: 2567: 2564: 2544: 2524: 2504: 2484: 2460: 2440: 2416: 2413: 2410: 2407: 2404: 2392: 2389: 2355:, the letters 2309: 2306: 2301: 2300: 2297: 2290: 2289:optimizations. 2281: 2278: 2215: 2212: 2137:most efficient 2130:most efficient 2116:is initial in 2105: 2098: 2091: 2084: 2077: 2066: 2052:comma category 2047: 2043: 2039: 2032: 2025: 2014: 1999: 1988: 1935:most efficient 1923:initial object 1896:most efficient 1877:most efficient 1857:most efficient 1852: 1849: 1829: 1823: 1820: 1807: 1804: 1801: 1798: 1795: 1792: 1789: 1786: 1783: 1780: 1777: 1774: 1771: 1751: 1731: 1713: 1712: 1701: 1698: 1695: 1692: 1655: 1649: 1646: 1643: 1621: 1598: 1592: 1589: 1586: 1564: 1544: 1524: 1501: 1481: 1461: 1437: 1417: 1393: 1373: 1349: 1346: 1326: 1323: 1320: 1317: 1314: 1311: 1305: 1299: 1296: 1293: 1271: 1250: 1230: 1204: 1193: 1192: 1181: 1178: 1175: 1172: 1169: 1166: 1160: 1154: 1151: 1148: 1143: 1140: 1137: 1134: 1131: 1128: 1125: 1119: 1113: 1110: 1107: 1102: 1097: 1094: 1090: 1050: 1047: 1032: 1008: 980: 956: 931: 928: 925: 904: 878: 857: 831: 806: 784: 763: 760: 757: 753: 748: 743: 740: 737: 734: 731: 728: 725: 720: 697: 694: 691: 687: 682: 677: 674: 671: 668: 665: 662: 659: 654: 630: 608: 581: 577: 574: 570: 565: 560: 557: 554: 551: 548: 545: 542: 537: 508: 504: 501: 497: 492: 487: 484: 481: 478: 475: 472: 469: 464: 442: 422: 407: 406: 395: 392: 389: 386: 383: 380: 374: 368: 365: 362: 357: 354: 351: 348: 345: 342: 339: 333: 327: 324: 321: 290: 268: 246: 224: 213: 212: 199: 194: 189: 184: 181: 159: 154: 149: 144: 141: 112: 88: 15: 9: 6: 4: 3: 2: 16907: 16896: 16893: 16892: 16890: 16875: 16872: 16870: 16869:Representable 16867: 16865: 16862: 16860: 16857: 16855: 16852: 16850: 16847: 16845: 16842: 16840: 16837: 16835: 16832: 16830: 16827: 16825: 16822: 16820: 16817: 16815: 16812: 16810: 16807: 16806: 16803: 16798: 16791: 16786: 16784: 16779: 16777: 16772: 16771: 16768: 16756: 16748: 16746: 16738: 16736: 16728: 16727: 16724: 16710: 16707: 16705: 16702: 16700: 16696: 16692: 16688: 16686: 16684: 16677: 16675: 16672: 16670: 16667: 16666: 16664: 16661: 16657: 16647: 16644: 16641: 16637: 16634: 16633: 16631: 16629: 16621: 16615: 16612: 16610: 16607: 16605: 16602: 16600: 16599:Tetracategory 16597: 16595: 16592: 16589: 16588:pseudofunctor 16585: 16582: 16581: 16579: 16577: 16569: 16566: 16562: 16557: 16554: 16552: 16549: 16547: 16544: 16542: 16539: 16537: 16534: 16532: 16529: 16527: 16524: 16522: 16519: 16517: 16513: 16507: 16506: 16503: 16499: 16494: 16490: 16485: 16467: 16464: 16462: 16459: 16457: 16454: 16452: 16449: 16447: 16444: 16442: 16439: 16437: 16434: 16432: 16431:Free category 16429: 16428: 16426: 16422: 16415: 16414:Vector spaces 16411: 16408: 16405: 16401: 16398: 16396: 16393: 16391: 16388: 16386: 16383: 16381: 16378: 16376: 16373: 16372: 16370: 16368: 16364: 16354: 16351: 16349: 16346: 16342: 16339: 16338: 16337: 16334: 16332: 16329: 16327: 16324: 16323: 16321: 16319: 16315: 16309: 16308:Inverse limit 16306: 16304: 16301: 16297: 16294: 16293: 16292: 16289: 16287: 16284: 16282: 16279: 16278: 16276: 16274: 16270: 16267: 16265: 16261: 16255: 16252: 16250: 16247: 16245: 16242: 16240: 16237: 16235: 16234:Kan extension 16232: 16230: 16227: 16225: 16222: 16220: 16217: 16215: 16212: 16210: 16207: 16205: 16202: 16198: 16195: 16193: 16190: 16188: 16185: 16183: 16180: 16178: 16175: 16173: 16170: 16169: 16168: 16165: 16164: 16162: 16158: 16154: 16147: 16143: 16139: 16132: 16127: 16125: 16120: 16118: 16113: 16112: 16109: 16102: 16098: 16094: 16090: 16086: 16082: 16079: 16076: 16075:Eugenia Cheng 16072: 16068: 16063: 16062: 16052: 16048: 16044: 16042:0-387-98403-8 16038: 16034: 16030: 16029: 16024: 16020: 16016: 16012: 16008: 16006:0-471-60922-6 16002: 15995: 15994: 15988: 15987: 15976: 15973: 15972:0-387-97710-4 15969: 15965: 15961: 15956: 15948: 15944: 15938: 15931: 15927: 15923: 15919: 15914: 15906: 15902: 15897: 15892: 15888: 15884: 15877: 15870: 15861: 15860:q-alg/9609018 15856: 15849: 15845: 15837: 15835: 15831: 15826: 15824: 15820: 15816: 15812: 15808: 15804: 15800: 15780: 15772: 15768: 15764: 15761: 15754: 15753: 15752: 15735: 15721: 15717: 15714: 15707: 15706: 15705: 15703: 15699: 15663: 15660: 15653: 15652: 15651: 15649: 15645: 15641: 15637: 15633: 15623: 15621: 15617: 15612: 15607: 15603: 15599: 15594: 15589: 15582: 15578: 15574: 15569: 15564: 15560: 15556: 15552: 15545: 15540: 15535: 15531: 15527: 15520: 15516: 15512: 15507: 15505: 15501: 15497: 15493: 15490:If a functor 15483: 15481: 15477: 15471: 15469: 15465: 15461: 15457: 15453: 15449: 15445: 15441: 15437: 15433: 15421:Relationships 15418: 15416: 15412: 15408: 15404: 15399: 15397: 15393: 15389: 15367: 15364: 15361: 15358: 15332: 15326: 15323: 15320: 15317: 15291: 15286: 15283: 15280: 15268: 15267: 15266: 15264: 15260: 15256: 15252: 15248: 15244: 15240: 15236: 15232: 15228: 15224: 15211: 15207: 15204: 15200: 15197: 15193: 15190: 15186: 15185: 15184: 15181: 15179: 15175: 15171: 15167: 15163: 15159: 15149: 15147: 15143: 15138: 15136: 15113: 15102: 15095: 15091: 15086: 15083: 15077: 15073: 15070: 15066: 15062: 15057: 15053: 15050: 15045: 15042: 15038: 15029: 15026: 15022: 15019: 15015: 15012: 15004: 15001: 14997: 14993: 14990: 14985: 14979: 14976: 14971: 14968: 14960: 14957: 14952: 14939: 14926: 14925: 14924: 14922: 14918: 14899: 14896: 14890: 14887: 14884: 14881: 14877: 14874: 14866: 14865: 14864: 14847: 14841: 14838: 14834: 14831: 14827: 14824: 14817: 14816: 14815: 14813: 14809: 14805: 14801: 14797: 14793: 14789: 14785: 14775: 14761: 14741: 14714: 14706: 14703: 14699: 14695: 14690: 14687: 14683: 14676: 14673: 14670: 14668: 14662: 14659: 14651: 14648: 14642: 14639: 14636: 14630: 14628: 14622: 14619: 14607: 14606: 14605: 14603: 14599: 14591: 14587: 14583: 14580: 14576: 14572: 14571: 14570: 14568: 14564: 14560: 14556: 14552: 14548: 14544: 14540: 14535: 14533: 14529: 14525: 14521: 14517: 14513: 14509: 14505: 14493: 14489: 14485: 14482: 14479: 14475: 14472: 14471: 14470: 14456: 14450: 14447: 14444: 14436: 14431: 14425: 14421: 14416: 14412: 14408: 14405: 14404: 14403: 14397: 14389: 14385: 14381: 14377: 14373: 14370: 14369: 14368: 14362: 14358: 14354: 14350: 14347: 14346: 14345: 14343: 14342: 14334: 14330: 14321: 14317: 14313: 14309: 14304: 14300: 14297: 14296: 14295: 14293: 14289: 14285: 14281: 14277: 14273: 14269: 14265: 14261: 14257: 14253: 14247: 14215: 14212: 14208: 14204: 14196: 14192: 14185: 14182: 14177: 14174: 14170: 14162: 14159: 14154: 14148: 14139: 14135: 14131: 14111: 14107: 14100: 14097: 14092: 14089: 14085: 14081: 14076: 14073: 14069: 14061: 14060: 14056: 14051: 14045: 14041: 14035: 14030: 14026: 14023:Substituting 14022: 14021: 14017: 14013: 14009: 14005: 14001: 13997: 13993: 13972: 13966: 13963: 13958: 13954: 13950: 13944: 13936: 13933: 13928: 13925: 13922: 13908: 13904: 13900: 13894: 13888: 13885: 13879: 13871: 13868: 13865: 13849: 13848: 13844: 13841: 13837: 13833: 13828: 13823: 13819: 13815: 13811: 13806: 13801: 13797: 13779: 13776: 13773: 13770: 13767: 13759: 13743: 13738: 13735: 13731: 13722: 13718: 13699: 13696: 13693: 13690: 13687: 13679: 13663: 13655: 13652: 13648: 13639: 13636: 13633: 13630: 13622: 13617: 13613: 13604: 13586: 13583: 13580: 13577: 13574: 13566: 13550: 13545: 13542: 13538: 13529: 13525: 13506: 13503: 13500: 13497: 13494: 13486: 13470: 13462: 13459: 13455: 13446: 13443: 13438: 13435: 13432: 13429: 13421: 13416: 13412: 13403: 13402: 13401: 13383: 13380: 13377: 13374: 13368: 13365: 13362: 13352: 13351: 13350: 13348: 13343: 13338: 13333: 13328: 13324: 13320: 13316: 13312: 13308: 13295: 13277: 13274: 13271: 13268: 13263: 13260: 13256: 13252: 13250: 13242: 13239: 13234: 13231: 13227: 13223: 13215: 13211: 13204: 13201: 13199: 13189: 13185: 13181: 13175: 13169: 13166: 13163: 13155: 13151: 13144: 13141: 13139: 13134: 13117: 13116: 13111: 13101: 13096: 13091: 13086: 13082: 13081: 13077: 13059: 13056: 13051: 13048: 13044: 13040: 13037: 13034: 13032: 13019: 13015: 13008: 13005: 13000: 12997: 12993: 12989: 12986: 12983: 12981: 12968: 12964: 12957: 12954: 12948: 12942: 12939: 12936: 12931: 12927: 12923: 12921: 12916: 12899: 12898: 12893: 12888: 12881: 12875: 12870: 12866: 12865: 12861: 12840: 12834: 12831: 12826: 12822: 12818: 12812: 12804: 12801: 12798: 12784: 12780: 12776: 12770: 12764: 12761: 12755: 12747: 12744: 12741: 12725: 12724: 12720: 12716: 12712: 12708: 12704: 12700: 12696: 12695: 12694: 12692: 12687: 12682: 12677: 12672: 12657: 12650: 12646: 12642: 12638: 12634: 12630: 12626: 12616: 12607: 12600: 12592: 12585: 12576: 12572: 12568: 12558: 12549: 12545: 12538: 12534: 12526: 12517: 12513: 12509: 12502: 12498: 12491: 12487: 12481: 12475: 12467: 12460: 12452: 12445: 12441: 12434: 12427: 12423: 12419: 12412: 12405: 12401: 12394: 12387: 12383: 12379: 12375: 12366: 12362: 12358: 12354: 12350: 12346: 12341: 12337: 12331: 12327: 12321: 12316: 12312: 12308: 12304: 12300: 12296: 12292: 12291: 12289: 12284: 12279: 12274: 12269: 12264: 12260: 12256: 12253: 12249: 12243: 12238: 12233: 12231:on morphisms. 12230: 12223: 12219: 12212: 12208: 12204: 12200: 12192: 12187: 12177: 12168: 12160: 12156: 12149: 12142: 12138: 12134: 12131: 12127: 12123: 12119: 12115: 12110: 12105: 12101: 12096: 12091: 12087: 12083: 12079: 12075: 12074: 12072: 12068: 12064: 12060: 12059: 12058: 12056: 12052: 12048: 12038: 12036: 12032: 12025: 12021: 12017: 12013: 12008: 12003: 11999: 11997: 11993: 11989: 11985: 11980: 11975: 11971: 11970: 11949: 11946: 11942: 11938: 11930: 11926: 11919: 11916: 11914: 11907: 11904: 11900: 11887: 11883: 11876: 11873: 11868: 11865: 11861: 11857: 11855: 11848: 11845: 11841: 11829: 11828: 11824: 11823: 11798: 11792: 11789: 11786: 11783: 11775: 11755: 11748: 11744: 11740: 11738: 11728: 11725: 11721: 11712: 11709: 11706: 11703: 11688: 11685: 11679: 11673: 11670: 11662: 11642: 11635: 11631: 11627: 11625: 11615: 11612: 11608: 11599: 11596: 11591: 11588: 11585: 11582: 11564: 11558: 11555: 11552: 11544: 11524: 11517: 11513: 11509: 11503: 11497: 11494: 11492: 11484: 11476: 11473: 11470: 11462: 11459: 11449: 11446: 11440: 11434: 11426: 11406: 11398: 11392: 11389: 11384: 11380: 11376: 11374: 11366: 11358: 11355: 11350: 11347: 11344: 11336: 11333: 11322: 11321: 11317: 11316: 11315: 11309: 11300: 11296: 11292: 11288: 11284: 11279: 11275: 11270: 11266: 11262: 11258: 11254: 11250: 11246: 11242: 11238: 11233: 11229: 11224: 11220: 11216: 11212: 11208: 11204: 11203: 11202: 11201: 11200: 11198: 11194: 11190: 11186: 11179: 11175: 11170: 11165: 11163: 11158: 11153: 11149: 11145: 11142: 11137: 11132: 11127: 11122: 11118: 11116: 11115:right adjoint 11112: 11108: 11104: 11100: 11098: 11094: 11090: 11086: 11083: 11079: 11078: 11077: 11075: 11071: 11067: 11062: 11054: 11040: 10976: 10973: 10945: 10931: 10928: 10901: 10897: 10890: 10887: 10884: 10876: 10871: 10855: 10852: 10848: 10844: 10841: 10835: 10832: 10826: 10823: 10820: 10786: 10783: 10780: 10760: 10757: 10754: 10751: 10748: 10742: 10736: 10705: 10652: 10643: 10626: 10620: 10614: 10611: 10605: 10602: 10599: 10576: 10556: 10553: 10550: 10547: 10544: 10538: 10532: 10501: 10499: 10487: 10485: 10480: 10479: 10423: 10403: 10380: 10357: 10337: 10317: 10312: 10299: 10283: 10276: 10273: 10270: 10266: 10254: 10243: 10240: 10236: 10232: 10229: 10220: 10217: 10214: 10211: 10205: 10202: 10197: 10185: 10184: 10182: 10161: 10153: 10149: 10145: 10139: 10136: 10133: 10125: 10121: 10116: 10113: 10107: 10104: 10101: 10098: 10087: 10071: 10065: 10059: 10056: 10049: 10046: 10043: 10039: 10027: 10016: 10013: 10009: 10005: 10002: 9993: 9990: 9987: 9984: 9978: 9975: 9970: 9958: 9957: 9940: 9934: 9914: 9911: 9908: 9888: 9885: 9876: 9865: 9862: 9858: 9837: 9815: 9790: 9768: 9764: 9743: 9740: 9734: 9728: 9705: 9697: 9694: 9690: 9686: 9683: 9663: 9660: 9654: 9648: 9625: 9617: 9614: 9610: 9606: 9603: 9596:we also have 9583: 9580: 9577: 9554: 9546: 9543: 9539: 9535: 9526: 9520: 9512: 9509: 9505: 9501: 9498: 9478: 9475: 9469: 9463: 9455: 9454: 9433: 9425: 9422: 9418: 9414: 9411: 9405: 9402: 9399: 9394: 9382: 9381: 9379: 9363: 9357: 9352: 9348: 9344: 9341: 9334: 9330: 9324: 9321: 9318: 9313: 9301: 9293: 9292: 9278: 9275: 9272: 9264: 9249: 9246: 9240: 9232: 9229: 9225: 9204: 9184: 9164: 9144: 9124: 9104: 9084: 9079: 9075: 9071: 9068: 9065: 9060: 9056: 9035: 9027: 9024: 9023: 9007: 8987: 8982: 8978: 8974: 8954: 8934: 8914: 8911: 8908: 8885: 8854: 8824: 8797: 8772: 8767: 8763: 8759: 8739: 8733: 8713: 8693: 8685: 8681: 8662: 8645: 8634: 8629: 8625: 8617: 8616: 8602: 8596: 8593: 8590: 8570: 8562: 8561: 8557: 8553: 8537: 8517: 8495: 8491: 8468: 8464: 8443: 8423: 8403: 8395: 8373: 8365: 8361: 8357: 8351: 8348: 8345: 8337: 8333: 8328: 8325: 8319: 8316: 8313: 8310: 8300: 8299: 8285: 8265: 8245: 8223: 8219: 8210: 8206: 8205: 8186: 8180: 8177: 8171: 8163: 8159: 8155: 8149: 8141: 8137: 8116: 8096: 8076: 8073: 8070: 8044: 8036: 8032: 8028: 8025: 8019: 8016: 7994: 7990: 7981: 7978: 7977: 7968: 7964: 7960: 7956: 7952: 7948: 7945: 7942: 7938: 7934: 7930: 7926: 7919:The functor Ο€ 7918: 7915: 7912: 7908: 7904: 7900: 7896: 7892: 7888: 7884: 7880: 7876: 7875:Equivalences. 7873: 7872: 7863: 7859: 7855: 7851: 7847: 7844:instead: the 7843: 7839: 7835: 7832: 7829: 7825: 7821: 7817: 7813: 7809: 7805: 7801: 7797: 7793: 7789: 7785: 7781: 7777: 7773: 7769: 7765: 7761: 7757: 7753: 7749: 7745: 7742: 7738: 7734: 7731: 7730: 7729: 7726: 7724: 7720: 7716: 7711: 7709: 7705: 7704:Galois theory 7701: 7697: 7693: 7689: 7685: 7681: 7677: 7664: 7660: 7656: 7652: 7651:Stone duality 7648: 7645: 7642: 7635: 7631: 7627: 7626: 7621: 7617: 7613: 7609: 7608: 7603: 7599: 7595: 7588: 7584: 7580: 7576: 7572: 7569: 7565: 7562: 7559: 7555: 7551: 7547: 7543: 7539: 7535: 7531: 7527: 7523: 7519: 7515: 7512: 7508: 7504: 7501: 7498: 7494: 7490: 7486: 7482: 7478: 7474: 7470: 7466: 7463: 7459: 7455: 7451: 7448: 7444: 7441: 7438: 7434: 7431:creating the 7430: 7426: 7422: 7418: 7414: 7410: 7406: 7402: 7398: 7395: 7394: 7385: 7381: 7377: 7374: 7371: 7367: 7363: 7359: 7355: 7351: 7350:abelian group 7347: 7343: 7339: 7335: 7331: 7328: 7325: 7321: 7317: 7313: 7309: 7305: 7301: 7297: 7293: 7289: 7286: 7283: 7279: 7272: 7265: 7261: 7258: 7255: 7248: 7244: 7237: 7233: 7230: 7227: 7223: 7219: 7215: 7212: 7208: 7204: 7200: 7196: 7192: 7188: 7185: 7182: 7178: 7174: 7170: 7165: 7160: 7156: 7153:, defined by 7152: 7148: 7144: 7140: 7136: 7132: 7128: 7124: 7120: 7116: 7112: 7108: 7104: 7102: 7098: 7095: 7091: 7087: 7083: 7079: 7075: 7071: 7067: 7063: 7059: 7055: 7051: 7047: 7043: 7039: 7035: 7031: 7027: 7023: 7019: 7015: 7012: 7009: 6993: 6986: 6983: 6979: 6975: 6971: 6969: 6964: 6961: 6957: 6953: 6949: 6945: 6943: 6938: 6937: 6923: 6919: 6915: 6914:vector spaces 6911: 6907: 6906: 6902: 6898: 6894: 6890: 6886: 6882: 6879:) to back to 6878: 6874: 6867: 6860: 6856: 6852: 6848: 6844: 6840: 6836: 6832: 6828: 6824: 6817: 6810: 6806: 6803: 6800: 6796: 6792: 6789: 6788: 6787: 6785: 6781: 6777: 6773: 6769: 6756: 6755: 6751: 6747: 6743: 6739: 6735: 6731: 6727: 6724: 6720: 6716: 6712: 6708: 6704: 6699: 6695: 6689: 6682: 6678: 6674: 6669: 6665: 6660: 6656: 6649: 6642: 6638: 6631: 6624: 6617: 6610: 6603: 6596: 6592: 6588: 6585: 6584: 6580: 6576: 6572: 6568: 6567: 6563: 6559: 6555: 6548: 6541: 6534: 6527: 6523: 6519: 6515: 6511: 6507: 6503: 6500: 6493: 6486: 6482: 6472: 6468: 6464: 6461:Let Ξ  : 6460: 6457: 6456: 6455: 6453: 6449: 6445: 6441: 6437: 6428: 6426: 6425:free functors 6422: 6418: 6409: 6407: 6403: 6399: 6395: 6391: 6370: 6366: 6359: 6351: 6347: 6329: 6326: 6322: 6313: 6309: 6289: 6286: 6274: 6270: 6263: 6258: 6253: 6250: 6247: 6244: 6235: 6232: 6228: 6222: 6217: 6214: 6206: 6205: 6204: 6202: 6186: 6183: 6180: 6177: 6174: 6171: 6166: 6162: 6153: 6149: 6147: 6143: 6139: 6135: 6117: 6114: 6110: 6101: 6097: 6093: 6089: 6085: 6081: 6060: 6056: 6049: 6041: 6037: 6018: 6015: 6006: 6003: 5999: 5993: 5988: 5985: 5982: 5979: 5967: 5963: 5956: 5951: 5946: 5943: 5936: 5935: 5934: 5932: 5916: 5913: 5910: 5907: 5904: 5901: 5896: 5892: 5883: 5879: 5865: 5862: 5859: 5856: 5850: 5847: 5844: 5833: 5829: 5827: 5823: 5818: 5814: 5810: 5806: 5802: 5798: 5794: 5790: 5788: 5784: 5780: 5776: 5760: 5754: 5751: 5748: 5745: 5740: 5736: 5727: 5723: 5719: 5715: 5694: 5690: 5686: 5683: 5680: 5669: 5665: 5649: 5643: 5640: 5637: 5634: 5629: 5625: 5616: 5612: 5608: 5604: 5600: 5596: 5594: 5593: 5587: 5583: 5567: 5564: 5561: 5555: 5552: 5547: 5543: 5534: 5530: 5526: 5522: 5518: 5502: 5499: 5496: 5490: 5487: 5482: 5478: 5470:. Let   5469: 5466:generated by 5465: 5461: 5457: 5454:For each set 5453: 5449: 5447: 5443: 5439: 5435: 5431: 5427: 5423: 5419: 5415: 5411: 5407: 5406: 5401: 5400: 5395: 5390: 5388: 5373: 5371: 5367: 5363: 5359: 5355: 5351: 5347: 5343: 5339: 5335: 5331: 5327: 5323: 5307: 5304: 5301: 5293: 5289: 5281: 5277: 5273: 5269: 5265: 5261: 5257: 5256: 5255: 5253: 5249: 5239: 5237: 5233: 5229: 5225: 5220: 5218: 5214: 5198: 5195: 5192: 5189: 5186: 5178: 5174: 5170: 5161: 5157: 5155: 5137: 5134: 5130: 5121: 5103: 5099: 5046: 5015: 5012: 5008: 5004: 4996: 4992: 4985: 4982: 4980: 4973: 4970: 4966: 4953: 4949: 4942: 4939: 4934: 4931: 4927: 4923: 4921: 4914: 4911: 4907: 4895: 4894: 4893: 4891: 4887: 4883: 4879: 4856: 4853: 4850: 4847: 4844: 4841: 4839: 4832: 4828: 4820: 4817: 4814: 4811: 4808: 4805: 4803: 4796: 4792: 4780: 4779: 4778: 4777: 4773: 4769: 4764: 4750: 4747: 4744: 4724: 4721: 4718: 4715: 4709: 4706: 4703: 4692: 4691: 4687: 4682: 4681: 4677: 4671: 4669: 4665: 4660: 4654: 4634: 4627: 4624: 4619: 4614: 4611: 4608: 4601: 4598: 4593: 4588: 4581: 4567: 4560: 4557: 4552: 4547: 4544: 4541: 4534: 4531: 4526: 4521: 4514: 4513: 4512: 4510: 4506: 4502: 4479: 4476: 4462: 4458: 4456: 4451: 4436: 4429: 4426: 4423: 4421: 4416: 4405: 4404: 4403: 4402: 4398: 4394: 4390: 4386: 4382: 4378: 4375: 4371: 4367: 4363: 4353: 4351: 4347: 4343: 4339: 4331: 4327: 4315: 4311: 4307: 4299: 4295: 4287: 4283: 4274: 4270: 4268: 4264: 4259: 4255: 4252: 4248: 4243: 4238: 4234: 4230: 4226: 4222: 4218: 4214: 4209: 4205: 4200: 4194: 4189: 4180: 4175: 4168: 4163: 4159: 4157: 4156: 4152: 4147: 4146: 4142: 4136: 4134: 4130: 4126: 4122: 4100: 4097: 4094: 4091: 4083: 4061: 4058: 4055: 4052: 4044: 4028: 4023: 4020: 4017: 4005: 4004: 4003: 3982: 3979: 3976: 3973: 3965: 3943: 3940: 3937: 3934: 3926: 3910: 3900: 3899: 3898: 3897: 3892: 3888: 3884: 3879: 3875: 3871: 3868: 3864: 3860: 3856: 3854: 3843: 3839: 3825: 3805: 3785: 3765: 3756: 3742: 3734: 3733:right adjoint 3718: 3698: 3677: 3674: 3667: 3664: 3661: 3641: 3638: 3632: 3629: 3624: 3620: 3615: 3611: 3607: 3598: 3592: 3586: 3566: 3560: 3557: 3554: 3534: 3521: 3517: 3503: 3500: 3495: 3491: 3487: 3481: 3475: 3455: 3446: 3440: 3437: 3434: 3411: 3405: 3399: 3396: 3393: 3373: 3353: 3327: 3321: 3315: 3309: 3306: 3301: 3297: 3276: 3253: 3247: 3227: 3207: 3187: 3167: 3159: 3143: 3123: 3115: 3099: 3093: 3090: 3087: 3078: 3064: 3056: 3040: 3020: 3000: 2993: 2990: 2986: 2983: 2960: 2957: 2952: 2948: 2945: 2942: 2933: 2927: 2921: 2918: 2913: 2909: 2888: 2882: 2879: 2876: 2856: 2843: 2839: 2837: 2832: 2818: 2815: 2809: 2803: 2800: 2795: 2791: 2767: 2761: 2755: 2752: 2749: 2729: 2720: 2714: 2711: 2708: 2688: 2668: 2648: 2636: 2630: 2624: 2621: 2616: 2612: 2591: 2568: 2562: 2542: 2522: 2502: 2482: 2474: 2458: 2438: 2430: 2414: 2408: 2405: 2402: 2388: 2386: 2382: 2378: 2374: 2370: 2366: 2362: 2358: 2354: 2350: 2346: 2342: 2337: 2335: 2331: 2327: 2323: 2319: 2315: 2305: 2298: 2295: 2291: 2287: 2286: 2285: 2277: 2275: 2271: 2267: 2263: 2258: 2256: 2252: 2248: 2244: 2240: 2236: 2231: 2229: 2225: 2221: 2211: 2209: 2205: 2201: 2196: 2194: 2190: 2186: 2182: 2178: 2174: 2170: 2166: 2162: 2158: 2154: 2150: 2146: 2142: 2138: 2133: 2131: 2127: 2123: 2119: 2115: 2111: 2104: 2097: 2090: 2083: 2080:implies that 2076: 2072: 2065: 2061: 2057: 2053: 2038: 2031: 2024: 2020: 2013: 2009: 2006:of the form ( 2005: 1998: 1994: 1987: 1983: 1979: 1975: 1971: 1967: 1963: 1959: 1955: 1951: 1946: 1944: 1940: 1936: 1932: 1928: 1924: 1920: 1915: 1913: 1909: 1905: 1901: 1897: 1892: 1890: 1886: 1882: 1878: 1874: 1870: 1866: 1862: 1858: 1848: 1846: 1837: 1836: 1828: 1819: 1802: 1799: 1796: 1793: 1787: 1781: 1778: 1775: 1772: 1749: 1729: 1722: 1718: 1717:Hilbert space 1699: 1696: 1693: 1690: 1683: 1682: 1681: 1679: 1675: 1670: 1619: 1562: 1542: 1522: 1513: 1499: 1479: 1472:. (Note that 1459: 1451: 1450:right adjoint 1435: 1415: 1407: 1391: 1371: 1363: 1360:is the right 1347: 1344: 1321: 1318: 1315: 1312: 1269: 1261: 1248: 1228: 1218: 1202: 1176: 1173: 1170: 1167: 1141: 1135: 1132: 1129: 1126: 1100: 1095: 1092: 1088: 1080: 1079: 1078: 1076: 1072: 1068: 1064: 1063: 1058: 1057: 1046: 996: 943: 929: 926: 923: 915: 902: 892: 876: 868: 855: 845: 829: 820: 782: 741: 735: 732: 729: 726: 675: 669: 666: 663: 660: 606: 558: 552: 549: 546: 543: 485: 479: 476: 473: 470: 440: 420: 412: 390: 387: 384: 381: 355: 349: 346: 343: 340: 310: 309: 308: 306: 266: 222: 182: 179: 142: 139: 132: 131: 130: 128: 75: 74:in topology. 73: 69: 65: 61: 57: 56:right adjoint 53: 49: 45: 41: 37: 33: 26: 22: 16819:Conservative 16813: 16679: 16660:Categorified 16564:n-categories 16515:Key concepts 16353:Direct limit 16336:Coequalizers 16254:Yoneda lemma 16203: 16160:Key concepts 16150:Key concepts 16069:playlist on 16026: 15992: 15974: 15963: 15955: 15946: 15937: 15925: 15913: 15886: 15882: 15869: 15848: 15827: 15822: 15817:〉 defines a 15814: 15810: 15806: 15802: 15798: 15796: 15750: 15701: 15697: 15696:is given by 15695: 15647: 15643: 15635: 15631: 15629: 15619: 15615: 15610: 15605: 15601: 15597: 15595: 15587: 15580: 15576: 15572: 15567: 15562: 15558: 15554: 15543: 15538: 15533: 15529: 15525: 15518: 15514: 15510: 15508: 15499: 15495: 15491: 15489: 15479: 15475: 15472: 15467: 15463: 15459: 15455: 15451: 15447: 15443: 15435: 15431: 15429: 15406: 15402: 15400: 15395: 15391: 15387: 15385: 15262: 15258: 15254: 15250: 15242: 15238: 15234: 15226: 15222: 15220: 15182: 15174:cocontinuous 15173: 15169: 15161: 15157: 15155: 15141: 15139: 15134: 15132: 14920: 14916: 14914: 14862: 14811: 14807: 14803: 14799: 14795: 14791: 14787: 14783: 14781: 14733: 14601: 14597: 14595: 14589: 14585: 14578: 14574: 14566: 14562: 14558: 14554: 14550: 14546: 14542: 14538: 14536: 14527: 14523: 14519: 14515: 14511: 14507: 14503: 14501: 14487: 14483: 14477: 14473: 14432: 14429: 14423: 14419: 14414: 14410: 14406: 14395: 14393: 14387: 14383: 14379: 14375: 14371: 14366: 14360: 14356: 14352: 14348: 14341:proper class 14339: 14332: 14331:come from a 14328: 14326: 14319: 14315: 14311: 14307: 14302: 14298: 14291: 14287: 14279: 14271: 14263: 14259: 14255: 14251: 14249: 14157: 14152: 14146: 14137: 14133: 14054: 14049: 14043: 14039: 14033: 14028: 14024: 14015: 14011: 14007: 14003: 13999: 13995: 13839: 13835: 13831: 13826: 13821: 13820:, and each ( 13817: 13813: 13809: 13804: 13799: 13720: 13716: 13527: 13523: 13399: 13346: 13341: 13336: 13331: 13326: 13322: 13318: 13314: 13310: 13306: 13304: 13109: 13099: 13094: 13089: 13084: 12895:), we obtain 12891: 12886: 12879: 12873: 12868: 12718: 12714: 12710: 12706: 12702: 12698: 12690: 12685: 12680: 12675: 12670: 12648: 12644: 12640: 12636: 12632: 12628: 12624: 12622: 12613: 12605: 12598: 12590: 12583: 12574: 12570: 12566: 12556: 12547: 12543: 12536: 12532: 12524: 12515: 12511: 12507: 12500: 12496: 12489: 12485: 12479: 12473: 12465: 12458: 12450: 12443: 12439: 12432: 12425: 12421: 12417: 12410: 12403: 12399: 12392: 12385: 12381: 12373: 12364: 12360: 12356: 12352: 12348: 12344: 12339: 12335: 12329: 12325: 12319: 12314: 12310: 12306: 12302: 12298: 12294: 12287: 12282: 12277: 12272: 12262: 12258: 12247: 12241: 12236: 12228: 12221: 12217: 12210: 12206: 12202: 12198: 12190: 12185: 12175: 12166: 12158: 12154: 12147: 12140: 12136: 12129: 12125: 12121: 12117: 12113: 12108: 12103: 12099: 12094: 12089: 12085: 12081: 12077: 12070: 12066: 12062: 12054: 12050: 12046: 12044: 12034: 12030: 12028: 12023: 12019: 12015: 12006: 12001: 11995: 11991: 11987: 11978: 11973: 11313: 11298: 11294: 11290: 11286: 11282: 11277: 11273: 11268: 11264: 11260: 11256: 11252: 11248: 11244: 11240: 11236: 11231: 11227: 11222: 11218: 11214: 11210: 11206: 11196: 11192: 11188: 11184: 11182: 11177: 11173: 11168: 11161: 11156: 11151: 11140: 11135: 11130: 11125: 11123:Ξ¦ : hom 11114: 11110: 11106: 11102: 11097:left adjoint 11096: 11092: 11088: 11084: 11076:consists of 11073: 11069: 11065: 11063: 11060: 11053:is "free".) 10872: 10644: 10502: 10497: 10495: 10481: 9025: 8556:topos theory 8207:The role of 7979: 7962: 7958: 7954: 7946: 7940: 7936: 7932: 7928: 7924: 7916: 7910: 7906: 7902: 7898: 7894: 7886: 7882: 7878: 7874: 7841: 7837: 7827: 7823: 7819: 7815: 7811: 7807: 7803: 7799: 7795: 7791: 7787: 7783: 7779: 7775: 7771: 7767: 7763: 7759: 7755: 7751: 7727: 7718: 7712: 7699: 7691: 7687: 7683: 7679: 7673: 7655:sober spaces 7646: 7633: 7629: 7623: 7619: 7615: 7611: 7605: 7601: 7597: 7586: 7578: 7574: 7570: 7563: 7557: 7545: 7541: 7537: 7533: 7525: 7521: 7517: 7506: 7502: 7488: 7484: 7476: 7472: 7468: 7464: 7453: 7449: 7442: 7436: 7428: 7424: 7416: 7412: 7400: 7396: 7375: 7370:model theory 7329: 7323: 7319: 7315: 7299: 7295: 7291: 7287: 7277: 7270: 7263: 7259: 7246: 7242: 7235: 7231: 7225: 7217: 7213: 7186: 7180: 7176: 7172: 7168: 7163: 7158: 7154: 7150: 7146: 7142: 7138: 7134: 7130: 7126: 7122: 7118: 7114: 7110: 7106: 7099: 7093: 7089: 7085: 7081: 7077: 7073: 7069: 7065: 7061: 7057: 7053: 7049: 7041: 7037: 7029: 7025: 7021: 7017: 7013: 7007: 6984: 6973: 6965: 6959: 6955: 6951: 6947: 6939: 6922:free product 6900: 6896: 6892: 6888: 6884: 6880: 6876: 6872: 6865: 6858: 6854: 6850: 6846: 6842: 6838: 6834: 6830: 6826: 6815: 6808: 6804: 6801: 6798: 6794: 6790: 6776:coequalizers 6766: 6749: 6745: 6741: 6737: 6733: 6729: 6725: 6722: 6718: 6710: 6706: 6702: 6697: 6693: 6687: 6680: 6676: 6672: 6667: 6663: 6658: 6654: 6647: 6640: 6636: 6629: 6622: 6615: 6608: 6601: 6594: 6590: 6586: 6561: 6557: 6553: 6546: 6539: 6532: 6525: 6521: 6517: 6513: 6509: 6501: 6498: 6491: 6484: 6477: 6470: 6466: 6462: 6458: 6434: 6417:Free objects 6415: 6405: 6401: 6397: 6393: 6389: 6349: 6345: 6311: 6307: 6305: 6200: 6151: 6150: 6145: 6141: 6137: 6133: 6099: 6095: 6091: 6087: 6083: 6079: 6039: 6035: 6033: 5930: 5881: 5880: 5831: 5830: 5825: 5821: 5816: 5812: 5808: 5804: 5800: 5796: 5792: 5791: 5786: 5782: 5778: 5774: 5725: 5721: 5717: 5713: 5667: 5663: 5617:. Let   5614: 5610: 5606: 5605:, the group 5602: 5598: 5597: 5591: 5585: 5581: 5532: 5528: 5524: 5520: 5516: 5467: 5463: 5459: 5455: 5451: 5450: 5445: 5441: 5437: 5429: 5425: 5421: 5417: 5409: 5403: 5397: 5393: 5391: 5384: 5365: 5361: 5357: 5349: 5341: 5333: 5329: 5325: 5291: 5285: 5279: 5275: 5271: 5267: 5263: 5259: 5245: 5231: 5227: 5223: 5221: 5216: 5212: 5172: 5168: 5166: 5153: 5119: 5037: 4889: 4885: 4881: 4877: 4875: 4775: 4771: 4767: 4765: 4689: 4685: 4684: 4679: 4675: 4674: 4672: 4667: 4663: 4658: 4652: 4649: 4504: 4500: 4498: 4396: 4392: 4388: 4384: 4380: 4376: 4369: 4365: 4361: 4359: 4349: 4345: 4341: 4337: 4329: 4317: 4313: 4309: 4305: 4297: 4293: 4288:) : Hom 4285: 4281: 4279: 4262: 4257: 4254: 4250: 4246: 4241: 4236: 4232: 4228: 4221:hom functors 4212: 4207: 4203: 4192: 4187: 4178: 4173: 4166: 4164: 4160: 4154: 4150: 4149: 4144: 4140: 4139: 4137: 4132: 4128: 4124: 4120: 4118: 4001: 3890: 3886: 3882: 3877: 3873: 3869: 3862: 3858: 3851: 3849: 3840: 3757: 3732: 3527:Again, this 3526: 3113: 3079: 3055:left adjoint 3054: 2848: 2833: 2428: 2394: 2384: 2380: 2376: 2372: 2368: 2364: 2360: 2356: 2352: 2348: 2344: 2340: 2338: 2333: 2329: 2325: 2321: 2317: 2313: 2311: 2302: 2293: 2283: 2273: 2269: 2265: 2261: 2259: 2254: 2250: 2246: 2242: 2238: 2234: 2232: 2227: 2223: 2219: 2217: 2207: 2203: 2199: 2197: 2192: 2188: 2184: 2180: 2176: 2172: 2168: 2164: 2160: 2156: 2152: 2148: 2144: 2140: 2136: 2134: 2129: 2125: 2121: 2117: 2113: 2109: 2102: 2095: 2088: 2081: 2074: 2070: 2063: 2059: 2055: 2036: 2029: 2022: 2018: 2011: 2007: 1996: 1992: 1985: 1981: 1977: 1973: 1969: 1965: 1961: 1957: 1953: 1949: 1947: 1942: 1934: 1931:optimization 1930: 1926: 1918: 1916: 1903: 1895: 1893: 1888: 1884: 1883:+1 for each 1880: 1876: 1860: 1856: 1854: 1841: 1833: 1826: 1714: 1677: 1673: 1671: 1514: 1449: 1406:left adjoint 1405: 1361: 1220: 1216: 1194: 1070: 1060: 1054: 1052: 944: 894: 890: 889:is called a 847: 843: 842:is called a 822:The functor 821: 775:for a fixed 599:for a fixed 408: 214: 76: 55: 52:left adjoint 51: 47: 39: 29: 16628:-categories 16604:Kan complex 16594:Tricategory 16576:-categories 16466:Subcategory 16224:Exponential 16192:Preadditive 16187:Pre-abelian 16085:Mathematica 16066:Adjunctions 15975:See page 58 15565:for which Ξ· 15536:for which Ξ΅ 15210:right exact 15135:composition 14778:Composition 13113:, we obtain 12456:, we have Ξ¦ 12106:, so that Ξ· 12000:Each pair ( 11972:Each pair ( 11271:-morphism Ξ¦ 11225:-morphism Ξ¦ 11176:called the 11160:called the 11113:called the 11095:called the 10492:Probability 10300:The subset 8209:quantifiers 7961:given by –× 7854:implication 7850:ring ideals 7113:is a right 6791:Coproducts. 6653:is a pair ( 6348:to the set 5807:to the set 5799:to a group 5387:free groups 5381:Free groups 5344:sign is an 2308:Conventions 1865:ring theory 995:equivalence 916:. We write 32:mathematics 16646:3-category 16636:2-category 16609:∞-groupoid 16584:Bicategory 16331:Coproducts 16291:Equalizers 16197:Bicategory 16051:0906.18001 16015:0695.18001 15984:References 15926:Dialectica 15622:inverses. 15604:such that 15415:biproducts 15217:Additivity 15203:left exact 15162:continuous 14498:Uniqueness 14284:continuous 14244:See also: 14235:Properties 13605:Let   13404:Let   13339:-,-) β†’ hom 12683:-,-) β†’ hom 12492:)) = G(x) 12280:-,-) β†’ hom 11255:-morphism 11209:-morphism 11205:For every 11133:–,–) β†’ hom 11101:A functor 11066:adjunction 10873:Then, the 8684:subobjects 7852:, and the 7554:continuous 7481:loop space 7462:suspension 7346:direct sum 6910:direct sum 6841:the pair ( 6823:direct sum 6768:Coproducts 6736:β†’ 0. Then 6512:the pair ( 6444:equalizers 5458:, the set 5420:, and let 5414:free group 5248:Daniel Kan 5038:Note that 4774:) are the 4199:bifunctors 3855:adjunction 3579:such that 2249:poses the 1217:adjunction 1053:The terms 40:adjunction 16849:Forgetful 16695:Symmetric 16640:2-functor 16380:Relations 16303:Pullbacks 16089:morphisms 15778:→ 15762:μ 15733:→ 15715:η 15674:→ 15620:two-sided 15333:≅ 15277:Φ 15196:coproduct 15096:ε 15071:ε 14998:η 14958:η 14894:→ 14882:∘ 14845:→ 14828:∘ 14762:∗ 14742:∘ 14704:− 14700:τ 14696:∗ 14688:− 14684:σ 14677:∘ 14674:ε 14660:ε 14652:η 14649:∘ 14643:σ 14640:∗ 14637:τ 14620:η 14584:Ο„ : 14573:Οƒ : 14454:→ 14394:for some 14240:Existence 14209:η 14205:∘ 14193:ε 14108:η 14098:∘ 14086:ε 13994:for each 13964:∘ 13955:ε 13934:− 13919:Φ 13905:η 13901:∘ 13862:Φ 13744:∈ 13664:∈ 13627:Φ 13614:η 13551:∈ 13471:∈ 13444:− 13426:Φ 13413:ε 13381:⊣ 13369:η 13363:ε 13269:∘ 13240:∘ 13228:η 13224:∘ 13212:ε 13186:η 13182:∘ 13164:∘ 13152:ε 13132:Ψ 13129:Φ 13041:∘ 13016:η 13006:∘ 12994:ε 12990:∘ 12965:η 12955:∘ 12937:∘ 12928:ε 12914:Φ 12911:Ψ 12832:∘ 12823:ε 12795:Ψ 12781:η 12777:∘ 12738:Φ 12709:and each 12697:For each 12658:⊣ 12205:) : 12135:For each 11943:η 11939:∘ 11927:ε 11884:η 11874:∘ 11862:ε 11756:∈ 11745:η 11700:Φ 11643:∈ 11632:ε 11597:− 11579:Φ 11525:∈ 11514:η 11510:∘ 11467:Φ 11407:∈ 11390:∘ 11381:ε 11356:− 11341:Φ 11150:Ξ΅ : 11041:δ 10977:δ 10974:⊣ 10946:μ 10935:↦ 10932:μ 10898:δ 10894:↦ 10885:δ 10853:− 10845:∘ 10842:μ 10839:→ 10836:μ 10821:μ 10784:∈ 10781:μ 10618:→ 10482:See also 10464:∀ 10444:∃ 10309:∀ 10274:∈ 10241:− 10233:∈ 10224:∀ 10221:∣ 10215:∈ 10194:∀ 10150:ϕ 10146:∧ 10122:ψ 10111:∃ 10108:∣ 10102:∈ 10047:∈ 10014:− 10006:∈ 9997:∃ 9994:∣ 9988:∈ 9967:∃ 9912:∈ 9886:∩ 9863:− 9812:∃ 9769:∗ 9741:⊆ 9695:− 9687:⊆ 9661:∈ 9615:− 9607:∈ 9581:∈ 9544:− 9536:⊆ 9510:− 9502:⊆ 9491:. We see 9476:⊆ 9456:Consider 9423:− 9415:⊆ 9409:↔ 9403:⊆ 9391:∃ 9353:∗ 9331:≅ 9310:∃ 9276:⊆ 9247:⊆ 9230:− 9076:× 9061:∗ 8979:× 8912:⊂ 8821:∀ 8794:∃ 8764:× 8737:→ 8652:⟶ 8630:∗ 8600:→ 8538:∧ 8518:∩ 8492:ϕ 8465:ψ 8362:ϕ 8358:∧ 8334:ψ 8323:∃ 8320:∣ 8314:∈ 8220:ψ 8181:φ 8178:∧ 8160:ϕ 8138:ϕ 8074:⊂ 8033:ϕ 8029:∣ 7991:ϕ 7739:(cf. the 7723:Kaplansky 7423:on a set 7302:from the 6994:⊔ 6968:semigroup 6920:, by the 6825:, and if 6797: : 6780:cokernels 6758:adjoints. 6367:ε 6323:η 6271:ε 6229:η 6184:η 6181:∘ 6178:ε 6111:ε 6057:η 6000:ε 5964:η 5917:η 5911:∘ 5905:ε 5863:⊣ 5851:η 5845:ε 5758:→ 5737:ε 5691:ε 5647:→ 5626:ε 5559:→ 5544:η 5494:→ 5479:η 5305:⊗ 5302:− 5199:η 5196:∘ 5193:ε 5009:η 5005:∘ 4993:ε 4950:η 4940:∘ 4928:ε 4884:and each 4854:η 4851:∘ 4848:ε 4821:η 4815:∘ 4809:ε 4748:⊣ 4722:⊣ 4710:η 4704:ε 4628:ε 4599:η 4558:ε 4535:η 4474:→ 4452:η 4433:→ 4417:ε 4328:for each 4225:morphisms 4068:→ 4014:Φ 3983:− 3974:− 3950:→ 3944:− 3938:− 3908:Φ 3671:→ 3639:∘ 3625:η 3612:η 3608:∘ 3564:→ 3492:η 3488:∘ 3453:→ 3403:→ 3313:→ 3298:η 3097:→ 2998:→ 2953:ϵ 2949:∘ 2919:∘ 2910:ϵ 2886:→ 2801:∘ 2792:ϵ 2759:→ 2727:→ 2646:→ 2613:ϵ 2412:→ 2141:formulaic 2042:) where S 1974:morphisms 1904:formulaic 1902:, and is 1889:formulaic 1861:formulaic 1806:⟩ 1791:⟨ 1785:⟩ 1770:⟨ 1694:⊣ 1345:φ 1203:φ 1142:≅ 1089:φ 927:⊣ 752:→ 736:− 686:→ 670:− 569:→ 544:− 496:→ 474:− 356:≅ 305:bijection 193:→ 153:→ 127:covariant 16889:Category 16864:Monoidal 16834:Enriched 16829:Diagonal 16809:Additive 16755:Glossary 16735:Category 16709:n-monoid 16662:concepts 16318:Colimits 16286:Products 16239:Morphism 16182:Concrete 16177:Additive 16167:Category 16093:functors 16081:WildCats 16025:(1998). 15832:and the 15494: : 15454: : 15253: : 15237: : 15178:colimits 15092:→ 15074:′ 15063:→ 15054:′ 15046:′ 15030:′ 15016:′ 15005:′ 14994:′ 14986:→ 14980:′ 14972:′ 14961:′ 14953:→ 14878:′ 14835:′ 14663:′ 14623:′ 14522:β€², then 14506: : 14422:∈ 14409: : 14351: : 14338:, not a 14306: : 14254: : 13321: : 13309: : 12721:, define 12713: : 12701: : 12639: : 12627: : 12442: : 12424: : 12347: : 12197:and get 12139: : 12112: : 12065: : 12049: : 12010:) is an 11289: : 11259: : 11243: : 11213: : 11105: : 11087: : 10773:and any 10498:solution 10484:powerset 9721:implies 8870:back to 7967:currying 7897: : 7881: : 7834:division 7750:is that 7719:antitone 7700:antitone 7581:between 7573: : 7540: : 7520: : 7391:Topology 7334:K-theory 7294: : 7222:algebras 7141: : 7125: : 7080: : 7056: : 7016:Suppose 6849:), then 6829: : 6721: : 6717:and let 6705: : 6621: : 6600: : 6587:Kernels. 6459:Products 6436:Products 6259:→ 6223:→ 5994:→ 5952:→ 5424: : 5396: : 5376:Examples 5290:, where 5270:) = hom( 5228:terminal 4763: . 4620:→ 4594:→ 4553:→ 4527:→ 4503:and the 4399:and two 4391: : 4379: : 4374:functors 4267:commutes 4249: : 4231: : 3885: : 3872: : 3867:functors 3678:′ 3633:′ 2994:′ 2961:′ 2375: : 2257:solves. 1980:between 1939:supremum 1830:β€”  1719:idea of 1075:Mac Lane 1067:cognates 997:between 869:, while 44:functors 16859:Logical 16824:Derived 16814:Adjoint 16797:Functor 16745:Outline 16704:n-group 16669:2-group 16624:Strict 16614:∞-topos 16410:Modules 16348:Pushout 16296:Kernels 16229:Functor 16172:Abelian 16071:YouTube 15905:1993102 15819:comonad 15549:as the 15466:, then 15394:, then 15261:, then 15189:product 14553:β€² then 13396: , 12098:) from 11982:) is a 11082:functor 9026:Example 7949:. In a 7842:adjoint 7715:duality 7659:duality 7594:sheaves 7532:. Then 7511:compact 7479:to the 7378:in the 7195:monoids 7161:) = hom 7072:. Then 7036:. Then 6934:Algebra 6918:modules 6784:colimit 6504:be the 6448:kernels 5432:be the 5350:natural 5328:), and 5242:History 5224:initial 4344:). Hom( 4300:) β†’ Hom 3853:hom-set 2294:adjoint 2268:, then 2237:is the 2187:is the 2183:. Then 2163:. Let 2128:* is a 1968:, with 1958:objects 1908:functor 1875:. The 1362:adjunct 1062:adjunct 1056:adjoint 411:natural 16874:Smooth 16691:Traced 16674:2-ring 16404:Fields 16390:Groups 16385:Magmas 16273:Limits 16049:  16039:  16013:  16003:  15970:  15903:  15626:Monads 15245:is an 15166:limits 14545:, and 14530:β€² are 14156:) for 14053:) for 12438:, any 12420:, any 12309:, as ( 12188:with Ξ· 12153:, as ( 11162:counit 9803:under 9137:along 7889:is an 7838:invert 7786:, let 7770:, let 7737:monads 7717:(i.e. 7674:Every 7670:Posets 7622:, the 7604:, the 7566:Every 7548:, the 7445:Given 7382:: see 7262:. Let 7203:groups 6978:monoid 6778:, and 6715:kernel 6701:. Let 6446:, and 6302:  6207:  6154:  5884:  5342:equals 5236:monads 4501:counit 4332:in Hom 3894:and a 1956:whose 1612:, and 1428:, and 1219:or an 16844:Exact 16799:types 16685:-ring 16572:Weak 16556:Topos 16400:Rings 15997:(PDF) 15901:JSTOR 15879:(PDF) 15855:arXiv 15840:Notes 15809:, Ξ΅, 15640:monad 14798:and γ€ˆ 14734:Here 14437:. If 14266:is a 14147:GX, X 14140:and Ξ΅ 14031:and Ξ· 12250:is a 12014:from 11986:from 9956:. So 9676:. So 9197:into 9117:into 9028:: In 8109:into 7546:KHaus 7522:KHaus 7507:KHaus 7368:, or 7340:on a 7332:. In 7243:Field 7211:field 7048:with 7032:is a 6499:Grp β†’ 6452:limit 6082:into 5356:from 5324:with 4656:and 1 4215:(the 4201:from 4181:–, –) 3468:with 3160:from 3112:is a 2783:with 2475:from 2427:is a 2318:right 2253:that 2220:start 1762:with 1262:. If 70:of a 16375:Sets 16037:ISBN 16001:ISBN 15968:ISBN 15947:nLab 15586:and 15575:and 15434:and 15409:are 15405:and 15233:and 15229:are 15225:and 14921:G' G 14919:and 14917:F F' 14810:and 14794:and 14526:and 14518:and 14382:) ∘ 14136:for 14027:for 14006:and 12359:) = 12355:) β†’ 12317:), Ξ· 12290:-). 12216:) β†’ 12164:), Ξ· 12092:), Ξ· 12033:and 11285:) = 11239:) = 11191:and 11178:unit 11072:and 9265:For 8812:and 8258:and 7909:and 7516:and 7505:Let 7452:and 7409:sets 7399:Let 7278:Ring 7271:Ring 7264:Ring 7189:The 7020:and 6916:and 6864:and 6752:β†’ 0. 6723:Ab β†’ 6614:and 6575:sets 6569:The 6545:and 6390:GFGX 6350:GFGX 6308:GFGX 6134:FGFY 6100:FGFY 6084:FGFY 6036:FGFY 5412:the 5392:Let 5258:hom( 5232:unit 4683:and 4666:and 4505:unit 4387:and 4368:and 4191:(–, 4183:and 4148:and 4127:and 3880:and 3861:and 3654:for 2324:and 2316:and 2314:left 2139:and 2069:and 2002:are 1991:and 1912:dual 1873:ring 1241:and 1059:and 1021:and 969:and 709:and 526:and 433:and 303:, a 259:and 101:and 16219:End 16209:CCC 16047:Zbl 16011:Zbl 15924:", 15920:, " 15891:doi 15821:in 15561:of 15553:of 15532:of 15482:). 15221:If 15180:). 14802:β€², 14600:β€², 14398:in 14333:set 14290:of 14274:of 14144:= Ξ¦ 14037:= Ξ¦ 13838:in 13834:to 13824:, Ξ· 13816:in 13812:to 13802:, Ξ΅ 13719:in 13526:in 13345:(-, 12877:= Ξ΅ 12689:(-, 12518:)) 12416:in 12398:in 12305:in 12297:in 12286:(-, 12102:to 12080:in 12022:in 12018:to 12004:, Ξ· 11994:in 11990:to 11976:, Ξ΅ 11297:in 11154:β†’ 1 11139:(–, 11064:An 10330:of 9335:Hom 9302:Hom 9036:Set 8967:in 8879:Sub 8848:Sub 8706:of 8656:Sub 8639:Sub 8416:of 7982:If 7877:If 7856:in 7766:in 7682:to 7542:Top 7526:Top 7487:of 7471:to 7467:of 7435:on 7407:to 7306:to 7300:Grp 7247:Dom 7236:Dom 7151:Mod 7131:Mod 7105:If 7094:Mod 7086:Mod 7070:Mod 7062:Mod 6942:rng 6912:of 6899:of 6793:If 6646:to 6573:of 6538:to 6522:Grp 6502:Grp 6467:Grp 6463:Grp 6398:FGX 6392:to 6312:FGX 6136:to 6090:of 5828:). 5815:to 5777:to 5724:to 5716:to 5664:FGX 5607:FGX 5584:to 5519:to 5460:GFY 5430:Set 5426:Grp 5405:Grp 5399:Set 5364:to 5266:), 5215:or 4888:in 4880:in 4662:on 4306:FYβ€² 4261:in 4240:in 4213:Set 4211:to 4185:hom 4171:hom 4131:in 4123:in 3735:to 3366:in 3269:in 3220:in 3180:to 3136:in 3057:to 3013:in 2681:in 2584:in 2535:in 2495:to 2451:in 2191:of 2054:of 2046:β†’ S 1976:in 1925:of 1869:rng 1672:If 1452:to 1448:is 1408:to 1404:is 1364:of 1215:an 893:or 846:or 795:in 619:in 413:in 279:in 235:in 30:In 16891:: 16697:) 16693:)( 16099:, 16095:, 16045:. 16031:. 16009:. 15945:. 15899:. 15887:87 15885:. 15881:. 15825:. 15807:FG 15702:GF 15700:= 15634:, 15606:FG 15513:, 15498:β†’ 15458:β†’ 15257:β†’ 15241:β†’ 15170:is 15158:is 14786:, 14588:β†’ 14577:β†’ 14565:, 14510:β†’ 14418:β†’ 14374:= 14355:β†’ 14310:β†’ 14278:: 14258:β†’ 14153:GX 14150:(1 14134:GX 14050:FY 14047:(1 14044:FY 14042:, 14025:FY 14016:GX 14014:β†’ 14010:: 14002:β†’ 14000:FY 13998:: 13822:FY 13800:GX 13325:β†’ 13317:, 13313:β†’ 13110:GX 13103:) 13097:(Ξ΅ 13093:= 13090:GX 12889:(Ξ· 12880:FY 12874:FY 12719:GX 12717:β†’ 12705:β†’ 12703:FY 12643:β†’ 12635:, 12631:β†’ 12601:) 12589:, 12577:) 12569:= 12550:) 12539:) 12531:= 12503:) 12464:, 12449:β†’ 12431:β†’ 12409:, 12391:, 12367:) 12338:, 12328:, 12240:β†’ 12146:β†’ 12116:β†’ 12069:β†’ 12053:β†’ 12002:FY 11974:GX 11293:β†’ 11291:FY 11276:, 11265:GX 11263:β†’ 11249:GX 11247:β†’ 11230:, 11217:β†’ 11215:FY 11174:GF 11172:β†’ 11152:FG 11146:A 11143:–) 11119:A 11109:β†’ 11091:β†’ 11080:A 10870:. 10642:. 7957:β†’ 7901:β†’ 7885:β†’ 7690:≀ 7628:. 7577:β†’ 7544:β†’ 7524:β†’ 7465:SX 7326:/. 7298:β†’ 7296:Ab 7276:β†’ 7245:β†’ 7145:β†’ 7143:Ab 7135:Ab 7133:β†’ 7088:β†’ 7064:β†’ 7028:β†’ 6903:). 6845:, 6835:Ab 6833:β†’ 6831:Ab 6814:, 6805:Ab 6799:Ab 6774:, 6770:, 6711:Ab 6709:β†’ 6686:= 6662:, 6628:β†’ 6607:β†’ 6516:, 6476:, 6465:β†’ 6442:, 6438:, 6408:. 6406:GX 6394:GX 6346:GX 6148:. 6146:FY 6142:FY 6138:FY 6092:FY 6080:FY 6040:FY 5813:FY 5809:GX 5797:FY 5779:GX 5722:FZ 5611:GX 5595:. 5582:FY 5529:GW 5464:FY 5448:: 5428:β†’ 5402:β†’ 5372:. 5360:Γ— 5282:)) 5274:, 5156:. 5154:FY 5091:, 4892:, 4395:β†’ 4383:β†’ 4360:A 4350:Gf 4348:, 4340:, 4338:FY 4326:Fg 4322:h 4318:f 4316:β†’ 4310:Xβ€² 4308:, 4296:, 4294:FY 4284:, 4282:Fg 4269:: 4256:β†’ 4237:Xβ€² 4235:β†’ 4206:Γ— 4195:–) 4158:. 4135:. 3889:β†’ 3876:β†’ 3850:A 3838:. 3755:. 3711:; 3516:. 3077:. 3033:; 2838:: 2831:. 2379:β†’ 2363:, 2359:, 2347:, 2343:, 2276:. 2208:R* 2206:β†’ 2200:R* 2195:. 2179:)= 2161:R* 2159:)= 2114:R* 2112:β†’ 2073:β†’ 2062:β†’ 2035:β†’ 2028:, 2021:β†’ 2017:, 2010:β†’ 1995:β†’ 1984:β†’ 1964:β†’ 1742:, 1669:. 1337:, 1073:, 942:. 819:. 584:op 511:op 129:) 38:, 16789:e 16782:t 16775:v 16689:( 16682:n 16680:E 16642:) 16638:( 16626:n 16590:) 16586:( 16574:n 16416:) 16412:( 16406:) 16402:( 16130:e 16123:t 16116:v 16103:. 16053:. 16017:. 15949:. 15907:. 15893:: 15863:. 15857:: 15823:C 15815:G 15813:Ξ· 15811:F 15803:F 15801:Ξ΅ 15799:G 15781:T 15773:2 15769:T 15765:: 15736:T 15727:D 15722:1 15718:: 15698:T 15679:D 15669:D 15664:: 15661:T 15648:D 15644:T 15642:γ€ˆ 15636:G 15632:F 15616:F 15611:D 15602:G 15598:F 15591:1 15588:C 15584:1 15581:D 15577:G 15573:F 15568:Y 15563:D 15559:Y 15555:D 15547:1 15544:D 15539:X 15534:C 15530:X 15526:C 15522:1 15519:C 15515:G 15511:F 15500:C 15496:D 15492:F 15480:C 15476:D 15468:G 15464:D 15460:D 15456:C 15452:G 15448:D 15444:C 15436:D 15432:C 15407:D 15403:C 15396:F 15392:F 15388:G 15371:) 15368:X 15365:G 15362:, 15359:Y 15356:( 15350:D 15344:m 15341:o 15338:h 15330:) 15327:X 15324:, 15321:Y 15318:F 15315:( 15309:C 15303:m 15300:o 15297:h 15292:: 15287:X 15284:, 15281:Y 15263:G 15259:D 15255:C 15251:G 15243:C 15239:D 15235:F 15227:D 15223:C 15212:. 15205:; 15142:C 15114:. 15108:C 15103:1 15087:G 15084:F 15078:G 15067:F 15058:G 15051:G 15043:F 15039:F 15027:F 15023:F 15020:G 15013:G 15002:F 14991:G 14977:F 14969:G 14945:E 14940:1 14900:. 14897:E 14891:C 14888:: 14885:G 14875:G 14848:C 14842:E 14839:: 14832:F 14825:F 14812:E 14808:D 14804:G 14800:F 14796:D 14792:C 14788:G 14784:F 14715:. 14712:) 14707:1 14691:1 14680:( 14671:= 14646:) 14634:( 14631:= 14602:G 14598:F 14592:β€² 14590:G 14586:G 14581:β€² 14579:F 14575:F 14567:G 14563:F 14559:G 14555:F 14551:G 14547:G 14543:G 14539:F 14528:G 14524:G 14520:G 14516:G 14512:C 14508:D 14504:F 14488:F 14484:F 14478:F 14474:F 14457:D 14451:C 14448:: 14445:F 14426:. 14424:C 14420:X 14415:i 14411:X 14407:t 14400:I 14396:i 14388:i 14384:f 14380:t 14378:( 14376:G 14372:h 14363:) 14361:X 14359:( 14357:G 14353:Y 14349:h 14336:I 14329:i 14323:) 14320:i 14316:X 14314:( 14312:G 14308:Y 14303:i 14299:f 14292:D 14288:Y 14280:G 14264:C 14260:D 14256:C 14252:G 14230:. 14216:X 14213:G 14202:) 14197:X 14189:( 14186:G 14183:= 14178:X 14175:G 14171:1 14158:f 14142:X 14138:Y 14129:, 14117:) 14112:Y 14104:( 14101:F 14093:Y 14090:F 14082:= 14077:Y 14074:F 14070:1 14055:g 14040:Y 14034:Y 14029:X 14012:Y 14008:g 14004:X 13996:f 13976:) 13973:g 13970:( 13967:F 13959:X 13951:= 13948:) 13945:g 13942:( 13937:1 13929:X 13926:, 13923:Y 13909:Y 13898:) 13895:f 13892:( 13889:G 13886:= 13883:) 13880:f 13877:( 13872:X 13869:, 13866:Y 13842:. 13840:D 13836:G 13832:Y 13827:Y 13818:C 13814:X 13810:F 13805:X 13783:) 13780:Y 13777:F 13774:, 13771:Y 13768:F 13765:( 13760:C 13755:m 13752:o 13749:h 13739:Y 13736:F 13732:1 13721:D 13717:Y 13703:) 13700:Y 13697:F 13694:G 13691:, 13688:Y 13685:( 13680:D 13675:m 13672:o 13669:h 13661:) 13656:Y 13653:F 13649:1 13645:( 13640:Y 13637:F 13634:, 13631:Y 13623:= 13618:Y 13590:) 13587:X 13584:G 13581:, 13578:X 13575:G 13572:( 13567:D 13562:m 13559:o 13556:h 13546:X 13543:G 13539:1 13528:C 13524:X 13510:) 13507:X 13504:, 13501:X 13498:G 13495:F 13492:( 13487:C 13482:m 13479:o 13476:h 13468:) 13463:X 13460:G 13456:1 13452:( 13447:1 13439:X 13436:, 13433:X 13430:G 13422:= 13417:X 13384:G 13378:F 13375:: 13372:) 13366:, 13360:( 13347:G 13342:D 13337:F 13335:( 13332:C 13327:D 13323:C 13319:G 13315:C 13311:D 13307:F 13278:g 13275:= 13272:g 13264:X 13261:G 13257:1 13253:= 13243:g 13235:X 13232:G 13221:) 13216:X 13208:( 13205:G 13202:= 13190:Y 13179:) 13176:g 13173:( 13170:F 13167:G 13161:) 13156:X 13148:( 13145:G 13142:= 13135:g 13107:Ξ· 13105:o 13100:X 13095:G 13085:G 13060:f 13057:= 13052:Y 13049:F 13045:1 13038:f 13035:= 13025:) 13020:Y 13012:( 13009:F 13001:Y 12998:F 12987:f 12984:= 12974:) 12969:Y 12961:( 12958:F 12952:) 12949:f 12946:( 12943:G 12940:F 12932:X 12924:= 12917:f 12892:Y 12887:F 12884:o 12869:F 12844:) 12841:g 12838:( 12835:F 12827:X 12819:= 12816:) 12813:g 12810:( 12805:X 12802:, 12799:Y 12785:Y 12774:) 12771:f 12768:( 12765:G 12762:= 12759:) 12756:f 12753:( 12748:X 12745:, 12742:Y 12715:Y 12711:g 12707:X 12699:f 12691:G 12686:D 12681:F 12679:( 12676:C 12671:G 12649:F 12645:D 12641:C 12637:G 12633:C 12629:D 12625:F 12606:y 12603:o 12599:f 12597:( 12594:0 12591:X 12587:0 12584:Y 12581:Ξ¦ 12579:o 12575:x 12573:( 12571:G 12567:y 12564:o 12560:0 12557:Y 12554:Ξ· 12552:o 12548:f 12546:( 12544:G 12541:o 12537:x 12535:( 12533:G 12528:1 12525:Y 12522:Ξ· 12520:o 12516:y 12514:( 12512:F 12510:( 12508:G 12505:o 12501:f 12499:( 12497:G 12494:o 12490:y 12488:( 12486:F 12483:o 12480:f 12477:o 12474:x 12472:( 12469:1 12466:X 12462:1 12459:Y 12454:0 12451:Y 12447:1 12444:Y 12440:y 12436:1 12433:X 12429:0 12426:X 12422:x 12418:D 12414:1 12411:Y 12407:0 12404:Y 12400:C 12396:1 12393:X 12389:0 12386:X 12382:G 12377:. 12374:Y 12371:Ξ· 12369:o 12365:f 12363:( 12361:G 12357:X 12353:Y 12351:( 12349:F 12345:f 12343:( 12340:X 12336:Y 12330:X 12326:Y 12320:Y 12315:Y 12313:( 12311:F 12307:D 12303:Y 12299:C 12295:X 12288:G 12283:D 12278:F 12276:( 12273:C 12263:F 12259:G 12254:. 12248:F 12245:o 12242:G 12237:D 12229:F 12225:1 12222:Y 12220:( 12218:F 12214:0 12211:Y 12209:( 12207:F 12203:f 12201:( 12199:F 12194:0 12191:Y 12186:f 12183:o 12179:1 12176:Y 12170:0 12167:Y 12162:0 12159:Y 12157:( 12155:F 12151:1 12148:Y 12144:0 12141:Y 12137:f 12130:F 12126:Y 12124:( 12122:F 12120:( 12118:G 12114:Y 12109:Y 12104:G 12100:Y 12095:Y 12090:Y 12088:( 12086:F 12082:D 12078:Y 12071:C 12067:D 12063:F 12055:D 12051:C 12047:G 12035:G 12031:F 12024:D 12020:G 12016:Y 12007:Y 11996:C 11992:X 11988:F 11979:X 11950:X 11947:G 11936:) 11931:X 11923:( 11920:G 11917:= 11908:X 11905:G 11901:1 11893:) 11888:Y 11880:( 11877:F 11869:Y 11866:F 11858:= 11849:Y 11846:F 11842:1 11805:) 11802:) 11799:Y 11796:( 11793:F 11790:G 11787:, 11784:Y 11781:( 11776:D 11771:m 11768:o 11765:h 11749:Y 11741:= 11734:) 11729:Y 11726:F 11722:1 11718:( 11713:Y 11710:F 11707:, 11704:Y 11692:) 11689:X 11686:, 11683:) 11680:X 11677:( 11674:G 11671:F 11668:( 11663:C 11658:m 11655:o 11652:h 11636:X 11628:= 11621:) 11616:X 11613:G 11609:1 11605:( 11600:1 11592:X 11589:, 11586:X 11583:G 11571:) 11568:) 11565:X 11562:( 11559:G 11556:, 11553:Y 11550:( 11545:D 11540:m 11537:o 11534:h 11518:Y 11507:) 11504:f 11501:( 11498:G 11495:= 11488:) 11485:f 11482:( 11477:X 11474:, 11471:Y 11463:= 11460:g 11453:) 11450:X 11447:, 11444:) 11441:Y 11438:( 11435:F 11432:( 11427:C 11422:m 11419:o 11416:h 11402:) 11399:g 11396:( 11393:F 11385:X 11377:= 11370:) 11367:g 11364:( 11359:1 11351:X 11348:, 11345:Y 11337:= 11334:f 11299:C 11295:X 11287:f 11283:g 11281:( 11278:X 11274:Y 11269:C 11261:Y 11257:g 11253:D 11245:Y 11241:g 11237:f 11235:( 11232:X 11228:Y 11223:D 11219:X 11211:f 11207:C 11197:D 11193:Y 11189:C 11185:X 11169:D 11157:C 11141:G 11136:D 11131:F 11129:( 11126:C 11111:D 11107:C 11103:G 11093:C 11089:D 11085:F 11074:D 11070:C 11020:E 10998:E 10970:E 10949:] 10943:[ 10939:E 10929:: 10925:E 10902:x 10891:x 10888:: 10856:1 10849:f 10833:: 10830:) 10827:f 10824:, 10818:( 10798:) 10794:R 10790:( 10787:M 10761:b 10758:+ 10755:x 10752:a 10749:= 10746:) 10743:x 10740:( 10737:f 10717:) 10713:R 10709:( 10706:M 10685:R 10664:) 10660:R 10656:( 10653:M 10630:) 10627:r 10624:( 10621:f 10615:r 10612:: 10609:) 10606:f 10603:, 10600:r 10597:( 10577:r 10557:b 10554:+ 10551:x 10548:a 10545:= 10542:) 10539:x 10536:( 10533:f 10512:R 10486:. 10476:. 10424:S 10404:f 10384:} 10381:y 10378:{ 10358:y 10338:Y 10318:S 10313:f 10284:. 10281:} 10277:S 10271:x 10267:. 10264:) 10261:] 10258:} 10255:y 10252:{ 10249:[ 10244:1 10237:f 10230:x 10227:( 10218:Y 10212:y 10209:{ 10206:= 10203:S 10198:f 10180:. 10168:} 10165:) 10162:x 10159:( 10154:S 10143:) 10140:y 10137:, 10134:x 10131:( 10126:f 10117:. 10114:x 10105:Y 10099:y 10096:{ 10072:. 10069:] 10066:S 10063:[ 10060:f 10057:= 10054:} 10050:S 10044:x 10040:. 10037:) 10034:] 10031:} 10028:y 10025:{ 10022:[ 10017:1 10010:f 10003:x 10000:( 9991:Y 9985:y 9982:{ 9979:= 9976:S 9971:f 9944:] 9941:S 9938:[ 9935:f 9915:Y 9909:y 9889:S 9883:] 9880:} 9877:y 9874:{ 9871:[ 9866:1 9859:f 9838:y 9816:f 9791:S 9765:f 9744:T 9738:] 9735:S 9732:[ 9729:f 9709:] 9706:T 9703:[ 9698:1 9691:f 9684:S 9664:T 9658:) 9655:x 9652:( 9649:f 9629:] 9626:T 9623:[ 9618:1 9611:f 9604:x 9584:S 9578:x 9558:] 9555:T 9552:[ 9547:1 9540:f 9533:] 9530:] 9527:S 9524:[ 9521:f 9518:[ 9513:1 9506:f 9499:S 9479:T 9473:] 9470:S 9467:[ 9464:f 9449:. 9437:] 9434:T 9431:[ 9426:1 9419:f 9412:S 9406:T 9400:S 9395:f 9364:, 9361:) 9358:T 9349:f 9345:, 9342:S 9339:( 9328:) 9325:T 9322:, 9319:S 9314:f 9306:( 9279:X 9273:S 9262:. 9250:X 9244:] 9241:T 9238:[ 9233:1 9226:f 9205:Y 9185:T 9165:f 9145:f 9125:Y 9105:T 9085:T 9080:Y 9072:X 9069:= 9066:T 9057:f 9020:. 9008:Y 8988:T 8983:Y 8975:X 8955:X 8935:f 8915:X 8909:S 8889:) 8886:Y 8883:( 8858:) 8855:X 8852:( 8825:f 8798:f 8773:T 8768:Y 8760:X 8740:Y 8734:T 8714:Y 8694:T 8666:) 8663:X 8660:( 8649:) 8646:Y 8643:( 8635:: 8626:f 8603:Y 8597:X 8594:: 8591:f 8571:Y 8496:S 8469:f 8444:x 8424:Y 8404:y 8380:} 8377:) 8374:x 8371:( 8366:S 8355:) 8352:y 8349:, 8346:x 8343:( 8338:f 8329:. 8326:x 8317:Y 8311:y 8308:{ 8286:X 8266:Y 8246:X 8224:f 8190:) 8187:y 8184:( 8175:) 8172:y 8169:( 8164:Y 8156:= 8153:) 8150:y 8147:( 8142:T 8117:Y 8097:T 8077:Y 8071:T 8051:} 8048:) 8045:y 8042:( 8037:Y 8026:y 8023:{ 8020:= 8017:Y 7995:Y 7963:A 7959:C 7955:C 7941:A 7937:U 7933:U 7929:D 7925:D 7921:0 7911:G 7907:F 7903:D 7899:C 7895:G 7887:C 7883:D 7879:F 7864:. 7830:. 7828:F 7824:G 7820:T 7816:S 7814:( 7812:F 7808:T 7806:( 7804:G 7800:S 7796:S 7792:S 7790:( 7788:F 7784:S 7780:T 7776:T 7774:( 7772:G 7768:C 7764:T 7760:D 7756:C 7743:) 7692:y 7688:x 7684:y 7680:x 7665:. 7637:βˆ— 7634:f 7630:f 7620:X 7616:Y 7612:f 7602:Y 7598:X 7590:βˆ— 7587:f 7579:Y 7575:X 7571:f 7558:X 7538:F 7534:G 7518:G 7499:. 7489:Y 7485:Y 7483:Ξ© 7477:X 7473:Y 7469:X 7454:Y 7450:X 7439:. 7437:Y 7429:H 7425:Y 7417:F 7413:G 7401:G 7324:G 7322:= 7320:G 7316:G 7292:G 7274:* 7267:* 7256:. 7250:m 7239:m 7228:. 7226:K 7220:- 7218:K 7214:K 7183:. 7181:F 7177:A 7173:A 7171:, 7169:M 7167:( 7164:Z 7159:A 7157:( 7155:G 7149:- 7147:R 7139:G 7129:- 7127:R 7123:F 7119:M 7115:R 7111:M 7107:R 7103:. 7096:. 7092:- 7090:R 7084:- 7082:S 7078:G 7074:F 7068:- 7066:S 7060:- 7058:R 7054:F 7050:S 7042:R 7038:S 7030:S 7026:R 7022:S 7018:R 7008:S 6985:S 6974:S 6970:. 6960:Z 6956:Z 6954:x 6952:R 6948:R 6944:. 6901:X 6897:b 6895:+ 6893:a 6889:b 6887:, 6885:a 6881:X 6877:X 6875:, 6873:X 6869:2 6866:X 6862:1 6859:X 6855:G 6851:F 6847:Y 6843:Y 6839:Y 6827:G 6819:2 6816:X 6812:1 6809:X 6802:β†’ 6795:F 6750:A 6746:A 6742:F 6738:G 6734:A 6730:A 6726:D 6719:F 6707:D 6703:G 6698:A 6694:g 6691:2 6688:f 6684:1 6681:f 6677:B 6673:g 6668:B 6664:g 6659:A 6655:g 6651:2 6648:f 6644:1 6641:f 6637:D 6633:2 6630:B 6626:2 6623:A 6619:2 6616:f 6612:1 6609:B 6605:1 6602:A 6598:1 6595:f 6591:D 6562:X 6560:Γ— 6558:X 6550:2 6547:X 6543:1 6540:X 6536:2 6533:X 6531:Γ— 6529:1 6526:X 6518:X 6514:X 6510:X 6495:2 6492:X 6490:Γ— 6488:1 6485:X 6480:2 6478:X 6474:1 6471:X 6402:X 6376:) 6371:X 6363:( 6360:G 6330:X 6327:G 6290:X 6287:G 6280:) 6275:X 6267:( 6264:G 6254:X 6251:G 6248:F 6245:G 6236:X 6233:G 6218:X 6215:G 6201:X 6187:G 6175:G 6172:= 6167:G 6163:1 6118:Y 6115:F 6096:y 6088:y 6066:) 6061:Y 6053:( 6050:F 6019:Y 6016:F 6007:Y 6004:F 5989:Y 5986:F 5983:G 5980:F 5973:) 5968:Y 5960:( 5957:F 5947:Y 5944:F 5931:Y 5914:F 5908:F 5902:= 5897:F 5893:1 5866:G 5860:F 5857:: 5854:) 5848:, 5842:( 5826:G 5824:, 5822:F 5820:( 5817:X 5805:Y 5801:X 5787:G 5785:, 5783:F 5775:Z 5761:X 5755:X 5752:G 5749:F 5746:: 5741:X 5726:X 5718:X 5714:F 5700:) 5695:X 5687:, 5684:X 5681:G 5678:( 5668:X 5650:X 5644:X 5641:G 5638:F 5635:: 5630:X 5615:X 5603:X 5592:Y 5586:W 5568:Y 5565:F 5562:G 5556:Y 5553:: 5548:Y 5533:W 5525:Y 5521:G 5517:Y 5503:Y 5500:F 5497:G 5491:Y 5488:: 5483:Y 5468:Y 5456:Y 5446:G 5442:F 5438:X 5422:G 5418:Y 5410:Y 5394:F 5366:Y 5362:A 5358:X 5334:A 5330:G 5326:A 5308:A 5292:F 5280:Y 5278:( 5276:G 5272:X 5268:Y 5264:X 5262:( 5260:F 5217:G 5213:F 5190:= 5187:1 5138:Y 5135:F 5131:1 5120:F 5104:F 5100:1 5077:C 5052:C 5047:1 5034:. 5016:X 5013:G 5002:) 4997:X 4989:( 4986:G 4983:= 4974:X 4971:G 4967:1 4959:) 4954:Y 4946:( 4943:F 4935:Y 4932:F 4924:= 4915:Y 4912:F 4908:1 4890:D 4886:Y 4882:C 4878:X 4857:G 4845:G 4842:= 4833:G 4829:1 4818:F 4812:F 4806:= 4797:F 4793:1 4772:Ξ· 4770:, 4768:Ξ΅ 4751:G 4745:F 4725:G 4719:F 4716:: 4713:) 4707:, 4701:( 4690:F 4686:G 4680:G 4676:F 4668:G 4664:F 4659:G 4653:F 4635:G 4625:G 4615:G 4612:F 4609:G 4602:G 4589:G 4568:F 4561:F 4548:F 4545:G 4542:F 4532:F 4522:F 4480:F 4477:G 4468:D 4463:1 4459:: 4442:C 4437:1 4430:G 4427:F 4424:: 4397:D 4393:C 4389:G 4385:C 4381:D 4377:F 4370:D 4366:C 4346:g 4342:X 4336:( 4334:C 4330:h 4324:o 4320:o 4314:h 4304:( 4302:C 4298:X 4292:( 4290:C 4286:f 4263:D 4258:Y 4253:β€² 4251:Y 4247:g 4242:C 4233:X 4229:f 4208:C 4204:D 4193:G 4188:D 4179:F 4177:( 4174:C 4155:F 4151:G 4145:G 4141:F 4133:D 4129:Y 4125:C 4121:X 4104:) 4101:X 4098:G 4095:, 4092:Y 4089:( 4084:D 4079:m 4076:o 4073:h 4065:) 4062:X 4059:, 4056:Y 4053:F 4050:( 4045:C 4040:m 4037:o 4034:h 4029:: 4024:X 4021:, 4018:Y 3998:. 3986:) 3980:G 3977:, 3971:( 3966:D 3961:m 3958:o 3955:h 3947:) 3941:, 3935:F 3932:( 3927:C 3922:m 3919:o 3916:h 3911:: 3891:D 3887:C 3883:G 3878:C 3874:D 3870:F 3863:D 3859:C 3826:F 3806:G 3786:G 3766:F 3743:F 3719:G 3699:D 3675:Y 3668:Y 3665:: 3662:g 3642:g 3630:Y 3621:= 3616:Y 3605:) 3602:) 3599:g 3596:( 3593:F 3590:( 3587:G 3567:C 3561:D 3558:: 3555:F 3535:F 3504:g 3501:= 3496:Y 3485:) 3482:f 3479:( 3476:G 3456:X 3450:) 3447:Y 3444:( 3441:F 3438:: 3435:f 3415:) 3412:X 3409:( 3406:G 3400:Y 3397:: 3394:g 3374:C 3354:X 3334:) 3331:) 3328:Y 3325:( 3322:F 3319:( 3316:G 3310:Y 3307:: 3302:Y 3277:C 3257:) 3254:Y 3251:( 3248:F 3228:D 3208:Y 3188:G 3168:Y 3144:D 3124:Y 3100:D 3094:C 3091:: 3088:G 3065:G 3041:F 3021:C 3001:X 2991:X 2987:: 2984:f 2958:X 2946:f 2943:= 2940:) 2937:) 2934:f 2931:( 2928:G 2925:( 2922:F 2914:X 2889:D 2883:C 2880:: 2877:G 2857:G 2819:f 2816:= 2813:) 2810:g 2807:( 2804:F 2796:X 2771:) 2768:X 2765:( 2762:G 2756:Y 2753:: 2750:g 2730:X 2724:) 2721:Y 2718:( 2715:F 2712:: 2709:f 2689:D 2669:Y 2649:X 2643:) 2640:) 2637:X 2634:( 2631:G 2628:( 2625:F 2622:: 2617:X 2592:D 2572:) 2569:X 2566:( 2563:G 2543:C 2523:X 2503:X 2483:F 2459:C 2439:X 2415:C 2409:D 2406:: 2403:F 2385:C 2381:C 2377:D 2373:F 2369:D 2365:g 2361:G 2357:Y 2353:C 2349:f 2345:F 2341:X 2334:D 2330:C 2326:D 2322:C 2296:. 2274:F 2270:G 2266:G 2262:F 2255:F 2247:G 2243:G 2235:F 2228:F 2224:F 2204:R 2193:G 2185:F 2181:S 2177:S 2175:( 2173:G 2169:S 2165:G 2157:R 2155:( 2153:F 2149:F 2126:R 2122:E 2118:E 2110:R 2106:1 2103:S 2099:2 2096:S 2092:2 2089:S 2085:1 2082:S 2078:2 2075:S 2071:R 2067:1 2064:S 2060:R 2056:R 2048:2 2044:1 2040:2 2037:S 2033:1 2030:S 2026:2 2023:S 2019:R 2015:1 2012:S 2008:R 2000:2 1997:S 1993:R 1989:1 1986:S 1982:R 1978:E 1970:S 1966:S 1962:R 1954:E 1950:R 1943:E 1927:E 1919:E 1885:r 1881:r 1803:x 1800:U 1797:, 1794:y 1788:= 1782:x 1779:, 1776:y 1773:T 1750:U 1730:T 1700:. 1697:G 1691:F 1678:G 1674:F 1654:D 1648:m 1645:o 1642:h 1620:G 1597:C 1591:m 1588:o 1585:h 1563:F 1543:F 1523:F 1500:F 1480:G 1460:F 1436:G 1416:G 1392:F 1372:f 1348:f 1325:) 1322:X 1319:, 1316:Y 1313:F 1310:( 1304:C 1298:m 1295:o 1292:h 1270:f 1249:G 1229:F 1180:) 1177:X 1174:G 1171:, 1168:Y 1165:( 1159:D 1153:m 1150:o 1147:h 1139:) 1136:X 1133:, 1130:Y 1127:F 1124:( 1118:C 1112:m 1109:o 1106:h 1101:: 1096:Y 1093:X 1031:D 1007:C 979:D 955:C 930:G 924:F 903:F 877:G 856:G 830:F 805:D 783:Y 762:t 759:e 756:S 747:C 742:: 739:) 733:G 730:, 727:Y 724:( 719:D 696:t 693:e 690:S 681:C 676:: 673:) 667:, 664:Y 661:F 658:( 653:C 629:C 607:X 580:t 576:e 573:S 564:D 559:: 556:) 553:X 550:G 547:, 541:( 536:D 507:t 503:e 500:S 491:D 486:: 483:) 480:X 477:, 471:F 468:( 463:C 441:Y 421:X 394:) 391:X 388:G 385:, 382:Y 379:( 373:D 367:m 364:o 361:h 353:) 350:X 347:, 344:Y 341:F 338:( 332:C 326:m 323:o 320:h 289:D 267:Y 245:C 223:X 198:D 188:C 183:: 180:G 158:C 148:D 143:: 140:F 111:D 87:C 27:.

Index

Adjunction (field theory)
Adjunction space
mathematics
category theory
functors
universal property
free group on a set
Stoneβ€“ΔŒech compactification
topological space
covariant
bijection
natural
equivalence
adjoint
adjunct
cognates
Mac Lane
Hilbert space
adjoint operators
Categories for the Working Mathematician
colimits/limits
ring theory
rng
ring
universal property
functor
dual
initial object
supremum
commutative triangles

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.

↑