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C*-algebra

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5051: 43: 1050: 2130: 321:, and are also used in algebraic formulations of quantum mechanics. Another active area of research is the program to obtain classification, or to determine the extent of which classification is possible, for separable simple 1473: 2404:, and are often not worried about the subtleties associated with an infinite number of dimensions. (Mathematicians usually use the asterisk, *, to denote the Hermitian adjoint.) †-algebras feature prominently in 751: 1356: 2239:
of matrix algebras. In fact, all C*-algebras that are finite dimensional as vector spaces are of this form, up to isomorphism. The self-adjoint requirement means finite-dimensional C*-algebras are
2627: 1518: 1409: 2311: 2057: 838: 1242: 1164: 675: 918: 581: 492: 641: 1475:, and therefore, a B*-algebra is also a C*-algebra. Conversely, the C*-condition implies the B*-condition. This is nontrivial, and can be proved without using the condition 941: 1692: 3521:
it also has representations of type II and type III. Thus for C*-algebras and locally compact groups, it is only meaningful to speak of type I and non type I properties.
382: 3151: 1966: 3298: 3258: 3194: 3027: 2987: 2931: 2895: 2847: 1838: 243: 2063: 1934: 1778: 1594: 1864: 1752: 1662: 1628: 3094: 1726: 4438: 408: 3338: 3318: 3214: 3114: 3067: 3047: 2951: 1904: 1884: 1802: 3819:. This is a somewhat dated reference, but is still considered as a high-quality technical exposition. It is available in English from North Holland press. 1539:. 'C' stood for 'closed'. In his paper Segal defines a C*-algebra as a "uniformly closed, self-adjoint algebra of bounded operators on a Hilbert space". 4940: 4540: 1551:
or by reduction to commutative C*-algebras. In the latter case, we can use the fact that the structure of these is completely determined by the
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John A. Holbrook, David W. Kribs, and Raymond Laflamme. "Noiseless Subsystems and the Structure of the Commutant in Quantum Error Correction."
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is non-abelian. In particular, the dual of a locally compact group is defined to be the primitive ideal space of the group C*-algebra. See
1414: 4195: 3503:)) is a type I von Neumann algebra. In fact it is sufficient to consider only factor representations, i.e. representations π for which π( 2416: 1547:
C*-algebras have a large number of properties that are technically convenient. Some of these properties can be established by using the
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Concrete C*-algebras of compact operators admit a characterization similar to Wedderburn's theorem for finite dimensional C*-algebras:
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implies that any C*-algebra has a universal enveloping W*-algebra, such that any homomorphism to a W*-algebra factors through it.
694: 4724: 4525: 4188: 1520:. For these reasons, the term B*-algebra is rarely used in current terminology, and has been replaced by the term 'C*-algebra'. 4418: 3793:. This book is widely regarded as a source of new research material, providing much supporting intuition, but it is difficult. 1306: 4271: 4069: 3835: 4266: 107: 2571: 1478: 1369: 79: 4616: 4705: 4596: 4423: 3894: 3854: 3813: 3787: 3757: 2507: 126: 86: 4975: 4241: 2268: 4620: 4210: 3468:, known as W* algebras before the 1960s, are a special kind of C*-algebra. They are required to be closed in the 2362:. This vector uniquely determines the isomorphism class of a finite-dimensional C*-algebra. In the language of 2026: 776: 4124: 4008: 1781: 1548: 1188: 1109: 64: 17: 652: 93: 4771: 4433: 3944: 3875: 1254: 5080: 5054: 4827: 4761: 4589: 4059: 2244: 865: 521: 333:
We begin with the abstract characterization of C*-algebras given in the 1943 paper by Gelfand and Naimark.
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yielded an abstract characterisation of C*-algebras making no reference to operators on a Hilbert space.
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attempted to establish a general framework for these algebras, which culminated in a series of papers on
75: 60: 5036: 4990: 4914: 4796: 4545: 4443: 4323: 3601: 3476: 1972: 170: 1045:{\displaystyle \|x\|^{2}=\|x^{*}x\|=\sup\{|\lambda |:x^{*}x-\lambda \,1{\text{ is not invertible}}\}.} 5031: 4847: 4550: 4413: 4246: 4231: 4039: 4003: 922:
which is sometimes called the B*-identity. For history behind the names C*- and B*-algebras, see the
415: 4883: 4781: 4684: 4142: 4132: 4013: 3937: 3454: 3117: 2156: 1980: 152: 1675: 4980: 4756: 4505: 4480: 4298: 4287: 3998: 3653: 3349: 3345: 3217: 53: 31: 3865: 2125:{\displaystyle 0\leq e_{\lambda }\leq e_{\mu }\leq 1\quad {\mbox{ whenever }}\lambda \leq \mu .} 354: 5011: 4955: 4919: 4356: 4346: 4341: 4049: 3469: 3157: 3123: 1939: 314: 202: 3267: 3227: 3163: 2996: 2956: 2900: 2864: 2816: 1807: 1257:, i.e. bounded with norm ≀ 1. Furthermore, an injective *-homomorphism between C*-algebras is 212: 4718: 4101: 3423: 2236: 1913: 1757: 1566: 318: 4714: 3692: 3676: 1843: 1731: 1637: 1603: 295:
of operators. These papers considered a special class of C*-algebras that are now known as
5075: 4994: 4515: 4494: 4408: 4293: 4256: 3763:. An excellent introduction to the subject, accessible for those with a knowledge of basic 3365: 3072: 2990: 2670: 2216: 2000: 1711: 1293: 163: 4581: 100: 8: 4960: 4898: 4612: 4318: 4054: 3764: 3605: 3465: 2397: 2232: 2181: 1552: 296: 140: 387: 4985: 4852: 4448: 4377: 4308: 4152: 4114: 3776: 3511: 3389: 3323: 3303: 3199: 3099: 3052: 3032: 2936: 2240: 1889: 1869: 1787: 1058: 322: 292: 2897:
under pointwise multiplication and addition. The involution is pointwise conjugation.
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becomes a C*-algebra if we consider matrices as operators on the Euclidean space,
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This condition automatically implies that the *-involution is isometric, that is,
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This article is about an area of mathematics. For the concept in rocketry, see
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The C*-identity is a very strong requirement. For instance, together with the
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However, if a C*-algebra has non-type I representations, then by results of
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Similarly, a closed two-sided ideal of a C*-algebra is itself a C*-algebra.
5016: 4669: 4639: 4303: 4157: 4098: 3904: 3771: 3627: 1705: 1524: 307: 4945: 4935: 4842: 4644: 4500: 4085: 3518: 3261: 2515: 2332:, is isomorphic (in a noncanonical way) to the full matrix algebra M(dim( 1631: 3491:
is of type I if and only if for all non-degenerate representations π of
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states that every commutative C*-algebra is *-isomorphic to the algebra
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Another important class of non-Hilbert C*-algebras includes the algebra
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This C*-algebra approach is used in the Haag–Kastler axiomatization of
1468:{\displaystyle \lVert xx^{*}\rVert =\lVert x\rVert \lVert x^{*}\rVert } 272: 188: 2415:
An immediate generalization of finite dimensional C*-algebras are the
1672:, even though this terminology conflicts with its use for elements of 3978: 3964: 853: 42: 4565: 4510: 3847:
Algebraic Methods in Statistical Mechanics and Quantum Field Theory
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A locally compact group is said to be of type I if and only if its
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this is immediate: consider the directed set of compact subsets of
2774: 2177: 1258: 2526:). It is also closed under involution; hence it is a C*-algebra. 2320:
is the set of minimal nonzero self-adjoint central projections of
923: 2393: 2466:, is *-isomorphic to a norm-closed adjoint closed subalgebra of 1535:), namely, the space of bounded operators on some Hilbert space 3828:
Characterizations of C*-algebras: The Gelfand-Naimark Theorems
3533:, one typically describes a physical system with a C*-algebra 2176:
Using approximate identities, one can show that the algebraic
2773:). For separable Hilbert spaces, it is the unique ideal. The 263:
C*-algebras were first considered primarily for their use in
3907:(1947), "Irreducible representations of operator algebras", 1979:
of a C*-algebra, which in turn can be used to construct the
1287: 746:{\displaystyle (\lambda x)^{*}={\overline {\lambda }}x^{*}.} 4611: 3589:) such that φ(1) = 1. The expected value of the observable 3096:
be a function of compact support which is identically 1 on
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will have a sequential approximate identity if and only if
1971:
This partially ordered subspace allows the definition of a
3344:. This characterization is one of the motivations for the 2243:, from which fact one can deduce the following theorem of 2685:
is isomorphic to the space of square summable sequences
2427:
The prototypical example of a C*-algebra is the algebra
1351:{\displaystyle \lVert xx^{*}\rVert =\lVert x\rVert ^{2}} 3524: 3429:. This is defined as the enveloping C*-algebra of the 2146:
has a sequential approximate identity. More generally,
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C*-algebras are now an important tool in the theory of
3368:, there is a unique (up to C*-isomorphism) C*-algebra 2104: 1634:. This cone is identical to the elements of the form 390: 357: 3645:, a unital subspace of a C*-algebra that is *-closed. 3561:
of the system is defined as a positive functional on
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on a C*-algebra, which in turn is used to define the
1942: 1916: 1892: 1872: 1846: 1810: 1790: 1760: 1734: 1714: 1678: 1640: 1606: 1569: 1481: 1417: 1372: 1309: 1191: 1112: 944: 868: 779: 697: 655: 590: 524: 438: 215: 3731:. Volume 2, Number 5, pp. 381–419. Oct 2003. 2669:) does not have an identity element, a sequential 2622:{\displaystyle A\cong \bigoplus _{i\in I}K(H_{i}),} 2485: 1513:{\displaystyle \lVert x\rVert =\lVert x^{*}\rVert } 1404:{\displaystyle \lVert x\rVert =\lVert x^{*}\rVert } 67:. Unsourced material may be challenged and removed. 4941:Spectral theory of ordinary differential equations 4541:Spectral theory of ordinary differential equations 3959: 3801: 3775: 3332: 3312: 3292: 3252: 3208: 3188: 3145: 3108: 3088: 3061: 3041: 3021: 2981: 2945: 2925: 2889: 2841: 2621: 2305: 2231:||·|| on matrices. The involution is given by the 2124: 2051: 1960: 1928: 1898: 1878: 1858: 1832: 1796: 1772: 1746: 1720: 1686: 1656: 1622: 1588: 1512: 1467: 1403: 1350: 1236: 1158: 1044: 912: 832: 745: 669: 635: 575: 486: 402: 376: 237: 4439:Schröder–Bernstein theorems for operator algebras 2933:has a multiplicative unit element if and only if 2195: 1697:The set of self-adjoint elements of a C*-algebra 283:and in a more mathematically developed form with 5067: 3537:with unit element; the self-adjoint elements of 3422:Of particular importance is the C*-algebra of a 2632:where the (C*-)direct sum consists of elements ( 2498:infinite-dimensional Hilbert space. The algebra 2289: 986: 1527:in 1947 to describe norm-closed subalgebras of 1249:In the case of C*-algebras, any *-homomorphism 3557:, the measurable quantities, of the system. A 4597: 3945: 3909:Bulletin of the American Mathematical Society 3392:, that is, every other continuous *-morphism 2180:of a C*-algebra by a closed proper two-sided 1261:. These are consequences of the C*-identity. 3140: 3127: 2417:approximately finite dimensional C*-algebras 2306:{\displaystyle A=\bigoplus _{e\in \min A}Ae} 1563:Self-adjoint elements are those of the form 1507: 1494: 1488: 1482: 1462: 1449: 1446: 1440: 1434: 1418: 1398: 1385: 1379: 1373: 1339: 1332: 1326: 1310: 1036: 989: 980: 964: 952: 945: 898: 891: 885: 869: 824: 811: 808: 802: 796: 780: 328: 3863: 2422: 2235:. More generally, one can consider finite 1728:. In this ordering, a self-adjoint element 1542: 4604: 4590: 3952: 3938: 3822: 3688: 3672: 3472:, which is weaker than the norm topology. 2849:of complex-valued continuous functions on 2800: 2396:for a finite-dimensional C*-algebra. The 2184:, with the natural norm, is a C*-algebra. 2052:{\displaystyle xe_{\lambda }\rightarrow x} 833:{\displaystyle \|x^{*}x\|=\|x\|\|x^{*}\|.} 245:of complex-valued continuous functions on 3920: 3593:, if the system is in state φ, is then φ( 3403:factors uniquely through π. The algebra 1680: 1288:Some history: B*-algebras and C*-algebras 1237:{\displaystyle \pi (x^{*})=\pi (x)^{*}\,} 1233: 1159:{\displaystyle \pi (xy)=\pi (x)\pi (y)\,} 1155: 1027: 663: 127:Learn how and when to remove this message 4894:Group algebra of a locally compact group 3804:Les C*-algĂšbres et leurs reprĂ©sentations 3355: 2003:. In fact, there is a directed family { 1558: 670:{\displaystyle \lambda \in \mathbb {C} } 201:is closed under the operation of taking 3796: 3744: 3482: 3460: 1362:in the given B*-algebra. (B*-condition) 14: 5068: 3770: 2953:is compact. As does any C*-algebra, 1596:. The set of elements of a C*-algebra 1523:The term C*-algebra was introduced by 1292:The term B*-algebra was introduced by 4585: 4272:Spectral theory of normal C*-algebras 4070:Spectral theory of normal C*-algebras 3933: 3903: 3881: 3715: 3704: 2548:), then there exists Hilbert spaces { 2431:of bounded (equivalently continuous) 913:{\displaystyle \|xx^{*}\|=\|x\|^{2},} 576:{\displaystyle (x+y)^{*}=x^{*}+y^{*}} 4267:Spectral theory of compact operators 3844: 3525:C*-algebras and quantum field theory 2681:) can be developed. To be specific, 2340:). The finite family indexed on min 1991:Quotients and approximate identities 487:{\displaystyle x^{**}=(x^{*})^{*}=x} 275:. This line of research began with 65:adding citations to reliable sources 36: 2392:) is the name occasionally used in 1664:. Elements of this cone are called 848:The first four identities say that 636:{\displaystyle (xy)^{*}=y^{*}x^{*}} 24: 4419:Cohen–Hewitt factorization theorem 3649:Gelfand–Naimark–Segal construction 3499:)″ (that is, the bicommutant of π( 2727:be the orthogonal projection onto 2262:isomorphic to a finite direct sum 1708:; the ordering is usually denoted 856:. The last identity is called the 25: 5092: 4424:Extensions of symmetric operators 3608:is associated with a C*-algebra. 2861:) forms a commutative C*-algebra 2765:) is a two-sided closed ideal of 2254:A finite-dimensional C*-algebra, 1701:naturally has the structure of a 159:. A particular case is that of a 155:satisfying the properties of the 27:Topological complex vector space 5050: 5049: 4976:Topological quantum field theory 4242:Positive operator-valued measure 3300:as C*-algebras, it follows that 2708:be the subspace of sequences of 2486:C*-algebras of compact operators 2474:) for a suitable Hilbert space, 1804:is non-negative, if and only if 180:with two additional properties: 139:In mathematics, specifically in 41: 4526:Rayleigh–Faber–Krahn inequality 3922:10.1090/S0002-9904-1947-08742-5 3116:. Such functions exist by the 2747:is an approximate identity for 2102: 410:with the following properties: 249:that vanish at infinity, where 52:needs additional citations for 3729:Quantum Information Processing 3721: 3709: 3698: 3682: 3666: 3287: 3281: 3247: 3241: 3183: 3177: 3016: 3010: 2976: 2970: 2920: 2914: 2884: 2878: 2836: 2830: 2613: 2600: 2196:Finite-dimensional C*-algebras 2043: 1549:continuous functional calculus 1224: 1217: 1208: 1195: 1152: 1146: 1140: 1134: 1125: 1116: 1001: 993: 708: 698: 601: 591: 538: 525: 469: 455: 361: 232: 226: 13: 1: 4772:Uniform boundedness principle 4434:Limiting absorption principle 3738: 3441:provides context for general 2639:) of the Cartesian product Π 2478:; this is the content of the 2462:. In fact, every C*-algebra, 4060:Singular value decomposition 3153:is an approximate identity. 2813:Hausdorff space. The space 2014:of self-adjoint elements of 1866:. Two self-adjoint elements 1687:{\displaystyle \mathbb {R} } 1300:that satisfy the condition: 725: 287:around 1933. Subsequently, 7: 4491:Hearing the shape of a drum 4174:Decomposition of a spectrum 3887:C*-algebras and W*-algebras 3871:Encyclopedia of Mathematics 3826:; Belfi, Victor A. (1986), 3750:An Invitation to C*-Algebra 3611: 2857:(defined in the article on 2697:. For each natural number 2410:quantum information science 2190: 1264:A bijective *-homomorphism 377:{\textstyle x\mapsto x^{*}} 171:continuous linear operators 147:(pronounced "C-star") is a 10: 5097: 4915:Invariant subspace problem 4079:Special Elements/Operators 3604:, where every open set of 3602:local quantum field theory 3495:the von Neumann algebra π( 2160:, i.e. a positive element 1973:positive linear functional 29: 5045: 5004: 4928: 4907: 4866: 4805: 4747: 4693: 4635: 4628: 4551:Superstrong approximation 4473: 4457: 4414:Banach algebra cohomology 4401: 4365: 4334: 4280: 4247:Projection-valued measure 4232:Borel functional calculus 4224: 4166: 4123: 4078: 4032: 4004:Projection-valued measure 3971: 3360:Given a Banach *-algebra 3146:{\displaystyle \{f_{K}\}} 2712:which vanish for indices 2157:strictly positive element 1961:{\displaystyle x-y\geq 0} 649:For every complex number 329:Abstract characterization 302:Around 1943, the work of 4884:Spectrum of a C*-algebra 4143:Spectrum of a C*-algebra 4014:Spectrum of a C*-algebra 3778:Non-commutative geometry 3659: 3553:) are thought of as the 3455:spectrum of a C*-algebra 3415:of the Banach *-algebra 3376:) and *-morphism π from 3293:{\displaystyle C_{0}(Y)} 3253:{\displaystyle C_{0}(X)} 3189:{\displaystyle C_{0}(X)} 3118:Tietze extension theorem 3022:{\displaystyle C_{0}(X)} 2982:{\displaystyle C_{0}(X)} 2926:{\displaystyle C_{0}(X)} 2890:{\displaystyle C_{0}(X)} 2842:{\displaystyle C_{0}(X)} 2423:C*-algebras of operators 2388:(or, more explicitly, a 1981:spectrum of a C*-algebra 1833:{\displaystyle x=s^{*}s} 1543:Structure of C*-algebras 238:{\displaystyle C_{0}(X)} 4981:Noncommutative geometry 4571:Wiener–Khinchin theorem 4506:Kuznetsov trace formula 4481:Almost Mathieu operator 4299:Banach function algebra 4288:Amenable Banach algebra 4045:Gelfand–Naimark theorem 3999:Noncommutative topology 3654:Jordan operator algebra 3350:noncommutative geometry 3346:noncommutative topology 3049:, and for each compact 2801:Commutative C*-algebras 2480:Gelfand–Naimark theorem 1929:{\displaystyle x\geq y} 1773:{\displaystyle x\geq 0} 1589:{\displaystyle x=x^{*}} 1253:between C*-algebras is 1033: is not invertible 931:spectral radius formula 315:unitary representations 32:characteristic velocity 5037:Tomita–Takesaki theory 5012:Approximation property 4956:Calculus of variations 4546:Sturm–Liouville theory 4444:Sherman–Takeda theorem 4324:Tomita–Takesaki theory 4099:Hermitian/Self-adjoint 4050:Gelfand representation 3849:, Wiley-Interscience, 3689:Doran & Belfi 1986 3673:Doran & Belfi 1986 3477:Sherman–Takeda theorem 3470:weak operator topology 3437:. The C*-algebra of 3334: 3314: 3294: 3254: 3210: 3190: 3158:Gelfand representation 3147: 3110: 3090: 3063: 3043: 3023: 2983: 2947: 2927: 2891: 2843: 2659: 2623: 2540:is a C*-subalgebra of 2326: 2307: 2126: 2053: 1962: 1930: 1900: 1880: 1860: 1859:{\displaystyle s\in A} 1834: 1798: 1774: 1748: 1747:{\displaystyle x\in A} 1722: 1688: 1658: 1657:{\displaystyle xx^{*}} 1624: 1623:{\displaystyle x^{*}x} 1590: 1514: 1469: 1405: 1352: 1238: 1160: 1073:, between C*-algebras 1046: 914: 860:and is equivalent to: 834: 747: 671: 637: 577: 488: 404: 378: 319:locally compact groups 239: 5032:Banach–Mazur distance 4995:Generalized functions 4040:Gelfand–Mazur theorem 3864:A.I. Shtern (2001) , 3569:-linear map φ : 3424:locally compact group 3413:C*-enveloping algebra 3356:C*-enveloping algebra 3335: 3315: 3295: 3255: 3211: 3191: 3148: 3111: 3091: 3089:{\displaystyle f_{K}} 3064: 3044: 3024: 2984: 2948: 2928: 2892: 2844: 2689:; we may assume that 2624: 2531: 2435:defined on a complex 2366:, this vector is the 2308: 2249: 2127: 2054: 1963: 1931: 1901: 1881: 1861: 1835: 1799: 1775: 1749: 1723: 1721:{\displaystyle \geq } 1689: 1659: 1625: 1591: 1559:Self-adjoint elements 1515: 1470: 1406: 1353: 1239: 1161: 1047: 915: 835: 748: 672: 638: 578: 489: 405: 379: 271:algebras of physical 240: 4777:Kakutani fixed-point 4762:Riesz representation 4516:Proto-value function 4495:Dirichlet eigenvalue 4409:Abstract index group 4294:Approximate identity 4257:Rigged Hilbert space 4133:Krein–Rutman theorem 3979:Involution/*-algebra 3808:, Gauthier-Villars, 3483:Type for C*-algebras 3466:Von Neumann algebras 3461:Von Neumann algebras 3366:approximate identity 3324: 3304: 3268: 3228: 3200: 3164: 3124: 3100: 3073: 3053: 3033: 2997: 2991:approximate identity 2957: 2937: 2901: 2865: 2817: 2671:approximate identity 2572: 2269: 2106: whenever  2064: 2027: 2001:approximate identity 1940: 1914: 1890: 1870: 1844: 1808: 1788: 1758: 1732: 1712: 1676: 1638: 1604: 1567: 1479: 1415: 1370: 1307: 1296:in 1946 to describe 1189: 1110: 942: 866: 777: 695: 653: 588: 522: 436: 388: 355: 297:von Neumann algebras 213: 61:improve this article 5081:Functional analysis 4961:Functional calculus 4920:Mahler's conjecture 4899:Von Neumann algebra 4613:Functional analysis 4319:Von Neumann algebra 4055:Polar decomposition 3765:functional analysis 3752:, Springer-Verlag, 3606:Minkowski spacetime 2233:conjugate transpose 1780:if and only if the 1553:Gelfand isomorphism 403:{\textstyle x\in A} 323:nuclear C*-algebras 187:is a topologically 141:functional analysis 4986:Riemann hypothesis 4685:Topological vector 4449:Unbounded operator 4378:Essential spectrum 4357:Schur–Horn theorem 4347:Bauer–Fike theorem 4342:Alon–Boppana bound 4335:Finite-Dimensional 4309:Nuclear C*-algebra 4153:Spectral asymmetry 3330: 3310: 3290: 3250: 3224:. Furthermore, if 3220:equipped with the 3206: 3186: 3143: 3106: 3086: 3059: 3039: 3019: 2979: 2943: 2923: 2887: 2855:vanish at infinity 2839: 2619: 2596: 2303: 2296: 2122: 2108: 2049: 1958: 1926: 1896: 1876: 1856: 1830: 1794: 1770: 1744: 1718: 1684: 1654: 1620: 1586: 1510: 1465: 1401: 1348: 1234: 1156: 1059:bounded linear map 1042: 910: 830: 743: 667: 633: 573: 484: 400: 374: 348:, together with a 344:over the field of 235: 5063: 5062: 4966:Integral operator 4743: 4742: 4579: 4578: 4556:Transfer operator 4531:Spectral geometry 4216:Spectral abscissa 4196:Approximate point 4138:Normal eigenvalue 3845:Emch, G. (1972), 3837:978-0-8247-7569-8 3638:Operator K-theory 3633:Hilbert C*-module 3531:quantum mechanics 3443:harmonic analysis 3333:{\displaystyle Y} 3313:{\displaystyle X} 3209:{\displaystyle X} 3109:{\displaystyle K} 3062:{\displaystyle K} 3042:{\displaystyle X} 2993:. In the case of 2946:{\displaystyle X} 2859:local compactness 2581: 2508:compact operators 2408:, and especially 2406:quantum mechanics 2402:Hermitian adjoint 2328:Each C*-algebra, 2278: 2107: 1899:{\displaystyle y} 1879:{\displaystyle x} 1797:{\displaystyle x} 1703:partially ordered 1298:Banach *-algebras 1034: 728: 277:Werner Heisenberg 265:quantum mechanics 151:together with an 137: 136: 129: 111: 16:(Redirected from 5088: 5053: 5052: 4971:Jones polynomial 4889:Operator algebra 4633: 4632: 4606: 4599: 4592: 4583: 4582: 4561:Transform theory 4281:Special algebras 4262:Spectral theorem 4225:Spectral Theorem 4065:Spectral theorem 3954: 3947: 3940: 3931: 3930: 3925: 3924: 3899: 3878: 3859: 3840: 3824:Doran, Robert S. 3818: 3807: 3798:Dixmier, Jacques 3792: 3781: 3762: 3732: 3725: 3719: 3713: 3707: 3702: 3696: 3686: 3680: 3675:, pp. 5–6, 3670: 3623:Banach *-algebra 3512:group C*-algebra 3507:)″ is a factor. 3411:) is called the 3402: 3339: 3337: 3336: 3331: 3319: 3317: 3316: 3311: 3299: 3297: 3296: 3291: 3280: 3279: 3259: 3257: 3256: 3251: 3240: 3239: 3216:is the space of 3215: 3213: 3212: 3207: 3195: 3193: 3192: 3187: 3176: 3175: 3152: 3150: 3149: 3144: 3139: 3138: 3115: 3113: 3112: 3107: 3095: 3093: 3092: 3087: 3085: 3084: 3068: 3066: 3065: 3060: 3048: 3046: 3045: 3040: 3028: 3026: 3025: 3020: 3009: 3008: 2988: 2986: 2985: 2980: 2969: 2968: 2952: 2950: 2949: 2944: 2932: 2930: 2929: 2924: 2913: 2912: 2896: 2894: 2893: 2888: 2877: 2876: 2848: 2846: 2845: 2840: 2829: 2828: 2734:. The sequence { 2628: 2626: 2625: 2620: 2612: 2611: 2595: 2450:of the operator 2448:adjoint operator 2433:linear operators 2390:†-closed algebra 2356:dimension vector 2312: 2310: 2309: 2304: 2295: 2245:Artin–Wedderburn 2131: 2129: 2128: 2123: 2109: 2105: 2095: 2094: 2082: 2081: 2058: 2056: 2055: 2050: 2042: 2041: 1985:GNS construction 1967: 1965: 1964: 1959: 1935: 1933: 1932: 1927: 1905: 1903: 1902: 1897: 1885: 1883: 1882: 1877: 1865: 1863: 1862: 1857: 1839: 1837: 1836: 1831: 1826: 1825: 1803: 1801: 1800: 1795: 1779: 1777: 1776: 1771: 1753: 1751: 1750: 1745: 1727: 1725: 1724: 1719: 1693: 1691: 1690: 1685: 1683: 1663: 1661: 1660: 1655: 1653: 1652: 1629: 1627: 1626: 1621: 1616: 1615: 1595: 1593: 1592: 1587: 1585: 1584: 1519: 1517: 1516: 1511: 1506: 1505: 1474: 1472: 1471: 1466: 1461: 1460: 1433: 1432: 1410: 1408: 1407: 1402: 1397: 1396: 1357: 1355: 1354: 1349: 1347: 1346: 1325: 1324: 1272:, in which case 1243: 1241: 1240: 1235: 1232: 1231: 1207: 1206: 1165: 1163: 1162: 1157: 1051: 1049: 1048: 1043: 1035: 1032: 1017: 1016: 1004: 996: 976: 975: 960: 959: 919: 917: 916: 911: 906: 905: 884: 883: 839: 837: 836: 831: 823: 822: 792: 791: 752: 750: 749: 744: 739: 738: 729: 721: 716: 715: 676: 674: 673: 668: 666: 642: 640: 639: 634: 632: 631: 622: 621: 609: 608: 582: 580: 579: 574: 572: 571: 559: 558: 546: 545: 493: 491: 490: 485: 477: 476: 467: 466: 451: 450: 409: 407: 406: 401: 383: 381: 380: 375: 373: 372: 289:John von Neumann 281:matrix mechanics 244: 242: 241: 236: 225: 224: 132: 125: 121: 118: 112: 110: 69: 45: 37: 21: 5096: 5095: 5091: 5090: 5089: 5087: 5086: 5085: 5066: 5065: 5064: 5059: 5041: 5005:Advanced topics 5000: 4924: 4903: 4862: 4828:Hilbert–Schmidt 4801: 4792:Gelfand–Naimark 4739: 4689: 4624: 4610: 4580: 4575: 4536:Spectral method 4521:Ramanujan graph 4469: 4453: 4429:Fredholm theory 4397: 4392:Shilov boundary 4388:Structure space 4366:Generalizations 4361: 4352:Numerical range 4330: 4314:Uniform algebra 4276: 4252:Riesz projector 4237:Min-max theorem 4220: 4206:Direct integral 4162: 4148:Spectral radius 4119: 4074: 4028: 4019:Spectral radius 3967: 3961:Spectral theory 3958: 3897: 3857: 3838: 3816: 3790: 3760: 3741: 3736: 3735: 3726: 3722: 3714: 3710: 3703: 3699: 3687: 3683: 3671: 3667: 3662: 3643:Operator system 3614: 3527: 3485: 3463: 3393: 3358: 3325: 3322: 3321: 3305: 3302: 3301: 3275: 3271: 3269: 3266: 3265: 3235: 3231: 3229: 3226: 3225: 3201: 3198: 3197: 3171: 3167: 3165: 3162: 3161: 3134: 3130: 3125: 3122: 3121: 3101: 3098: 3097: 3080: 3076: 3074: 3071: 3070: 3054: 3051: 3050: 3034: 3031: 3030: 3004: 3000: 2998: 2995: 2994: 2964: 2960: 2958: 2955: 2954: 2938: 2935: 2934: 2908: 2904: 2902: 2899: 2898: 2872: 2868: 2866: 2863: 2862: 2824: 2820: 2818: 2815: 2814: 2811:locally compact 2803: 2746: 2739: 2732: 2725: 2706: 2655: 2648: 2637: 2607: 2603: 2585: 2573: 2570: 2569: 2564: 2553: 2488: 2425: 2376: 2353: 2282: 2270: 2267: 2266: 2227:, and use the 2198: 2193: 2103: 2090: 2086: 2077: 2073: 2065: 2062: 2061: 2037: 2033: 2028: 2025: 2024: 2013: 2009: 1995:Any C*-algebra 1993: 1941: 1938: 1937: 1915: 1912: 1911: 1891: 1888: 1887: 1871: 1868: 1867: 1845: 1842: 1841: 1821: 1817: 1809: 1806: 1805: 1789: 1786: 1785: 1759: 1756: 1755: 1733: 1730: 1729: 1713: 1710: 1709: 1679: 1677: 1674: 1673: 1648: 1644: 1639: 1636: 1635: 1630:forms a closed 1611: 1607: 1605: 1602: 1601: 1580: 1576: 1568: 1565: 1564: 1561: 1545: 1501: 1497: 1480: 1477: 1476: 1456: 1452: 1428: 1424: 1416: 1413: 1412: 1392: 1388: 1371: 1368: 1367: 1342: 1338: 1320: 1316: 1308: 1305: 1304: 1290: 1280:are said to be 1227: 1223: 1202: 1198: 1190: 1187: 1186: 1111: 1108: 1107: 1031: 1012: 1008: 1000: 992: 971: 967: 955: 951: 943: 940: 939: 926:section below. 901: 897: 879: 875: 867: 864: 863: 818: 814: 787: 783: 778: 775: 774: 734: 730: 720: 711: 707: 696: 693: 692: 662: 654: 651: 650: 627: 623: 617: 613: 604: 600: 589: 586: 585: 567: 563: 554: 550: 541: 537: 523: 520: 519: 472: 468: 462: 458: 443: 439: 437: 434: 433: 389: 386: 385: 368: 364: 356: 353: 352: 346:complex numbers 331: 255:locally compact 220: 216: 214: 211: 210: 133: 122: 116: 113: 70: 68: 58: 46: 35: 28: 23: 22: 15: 12: 11: 5: 5094: 5084: 5083: 5078: 5061: 5060: 5058: 5057: 5046: 5043: 5042: 5040: 5039: 5034: 5029: 5024: 5022:Choquet theory 5019: 5014: 5008: 5006: 5002: 5001: 4999: 4998: 4988: 4983: 4978: 4973: 4968: 4963: 4958: 4953: 4948: 4943: 4938: 4932: 4930: 4926: 4925: 4923: 4922: 4917: 4911: 4909: 4905: 4904: 4902: 4901: 4896: 4891: 4886: 4881: 4876: 4874:Banach algebra 4870: 4868: 4864: 4863: 4861: 4860: 4855: 4850: 4845: 4840: 4835: 4830: 4825: 4820: 4815: 4809: 4807: 4803: 4802: 4800: 4799: 4797:Banach–Alaoglu 4794: 4789: 4784: 4779: 4774: 4769: 4764: 4759: 4753: 4751: 4745: 4744: 4741: 4740: 4738: 4737: 4732: 4727: 4725:Locally convex 4722: 4708: 4703: 4697: 4695: 4691: 4690: 4688: 4687: 4682: 4677: 4672: 4667: 4662: 4657: 4652: 4647: 4642: 4636: 4630: 4626: 4625: 4609: 4608: 4601: 4594: 4586: 4577: 4576: 4574: 4573: 4568: 4563: 4558: 4553: 4548: 4543: 4538: 4533: 4528: 4523: 4518: 4513: 4508: 4503: 4498: 4488: 4486:Corona theorem 4483: 4477: 4475: 4471: 4470: 4468: 4467: 4465:Wiener algebra 4461: 4459: 4455: 4454: 4452: 4451: 4446: 4441: 4436: 4431: 4426: 4421: 4416: 4411: 4405: 4403: 4399: 4398: 4396: 4395: 4385: 4383:Pseudospectrum 4380: 4375: 4373:Dirac spectrum 4369: 4367: 4363: 4362: 4360: 4359: 4354: 4349: 4344: 4338: 4336: 4332: 4331: 4329: 4328: 4327: 4326: 4316: 4311: 4306: 4301: 4296: 4290: 4284: 4282: 4278: 4277: 4275: 4274: 4269: 4264: 4259: 4254: 4249: 4244: 4239: 4234: 4228: 4226: 4222: 4221: 4219: 4218: 4213: 4208: 4203: 4198: 4193: 4192: 4191: 4186: 4181: 4170: 4168: 4164: 4163: 4161: 4160: 4155: 4150: 4145: 4140: 4135: 4129: 4127: 4121: 4120: 4118: 4117: 4112: 4104: 4096: 4088: 4082: 4080: 4076: 4075: 4073: 4072: 4067: 4062: 4057: 4052: 4047: 4042: 4036: 4034: 4030: 4029: 4027: 4026: 4024:Operator space 4021: 4016: 4011: 4006: 4001: 3996: 3991: 3986: 3984:Banach algebra 3981: 3975: 3973: 3972:Basic concepts 3969: 3968: 3957: 3956: 3949: 3942: 3934: 3928: 3927: 3901: 3895: 3879: 3861: 3855: 3842: 3836: 3820: 3814: 3794: 3788: 3768: 3758: 3740: 3737: 3734: 3733: 3720: 3708: 3697: 3681: 3664: 3663: 3661: 3658: 3657: 3656: 3651: 3646: 3640: 3635: 3630: 3625: 3620: 3618:Banach algebra 3613: 3610: 3581:) ≄ 0 for all 3526: 3523: 3484: 3481: 3462: 3459: 3357: 3354: 3329: 3309: 3289: 3286: 3283: 3278: 3274: 3249: 3246: 3243: 3238: 3234: 3222:weak* topology 3205: 3185: 3182: 3179: 3174: 3170: 3142: 3137: 3133: 3129: 3105: 3083: 3079: 3058: 3038: 3018: 3015: 3012: 3007: 3003: 2978: 2975: 2972: 2967: 2963: 2942: 2922: 2919: 2916: 2911: 2907: 2886: 2883: 2880: 2875: 2871: 2838: 2835: 2832: 2827: 2823: 2802: 2799: 2795:Calkin algebra 2742: 2737: 2730: 2723: 2704: 2653: 2646: 2635: 2630: 2629: 2618: 2615: 2610: 2606: 2602: 2599: 2594: 2591: 2588: 2584: 2580: 2577: 2556: 2551: 2518:subalgebra of 2487: 2484: 2424: 2421: 2374: 2354:is called the 2349: 2344:given by {dim( 2314: 2313: 2302: 2299: 2294: 2291: 2288: 2285: 2281: 2277: 2274: 2200:The algebra M( 2197: 2194: 2192: 2189: 2174: 2173: 2142:is separable, 2135: 2134: 2133: 2132: 2121: 2118: 2115: 2112: 2101: 2098: 2093: 2089: 2085: 2080: 2076: 2072: 2069: 2059: 2048: 2045: 2040: 2036: 2032: 2011: 2007: 1992: 1989: 1957: 1954: 1951: 1948: 1945: 1925: 1922: 1919: 1895: 1875: 1855: 1852: 1849: 1829: 1824: 1820: 1816: 1813: 1793: 1769: 1766: 1763: 1743: 1740: 1737: 1717: 1682: 1668:(or sometimes 1651: 1647: 1643: 1619: 1614: 1610: 1583: 1579: 1575: 1572: 1560: 1557: 1544: 1541: 1509: 1504: 1500: 1496: 1493: 1490: 1487: 1484: 1464: 1459: 1455: 1451: 1448: 1445: 1442: 1439: 1436: 1431: 1427: 1423: 1420: 1400: 1395: 1391: 1387: 1384: 1381: 1378: 1375: 1364: 1363: 1345: 1341: 1337: 1334: 1331: 1328: 1323: 1319: 1315: 1312: 1289: 1286: 1270:C*-isomorphism 1247: 1246: 1245: 1244: 1230: 1226: 1222: 1219: 1216: 1213: 1210: 1205: 1201: 1197: 1194: 1181: 1180: 1169: 1168: 1167: 1166: 1154: 1151: 1148: 1145: 1142: 1139: 1136: 1133: 1130: 1127: 1124: 1121: 1118: 1115: 1102: 1101: 1083:*-homomorphism 1055: 1054: 1053: 1052: 1041: 1038: 1030: 1026: 1023: 1020: 1015: 1011: 1007: 1003: 999: 995: 991: 988: 985: 982: 979: 974: 970: 966: 963: 958: 954: 950: 947: 909: 904: 900: 896: 893: 890: 887: 882: 878: 874: 871: 843: 842: 841: 840: 829: 826: 821: 817: 813: 810: 807: 804: 801: 798: 795: 790: 786: 782: 769: 768: 756: 755: 754: 753: 742: 737: 733: 727: 724: 719: 714: 710: 706: 703: 700: 687: 686: 665: 661: 658: 646: 645: 644: 643: 630: 626: 620: 616: 612: 607: 603: 599: 596: 593: 583: 570: 566: 562: 557: 553: 549: 544: 540: 536: 533: 530: 527: 514: 513: 497: 496: 495: 494: 483: 480: 475: 471: 465: 461: 457: 454: 449: 446: 442: 428: 427: 399: 396: 393: 371: 367: 363: 360: 342:Banach algebra 336:A C*-algebra, 330: 327: 304:Israel Gelfand 285:Pascual Jordan 234: 231: 228: 223: 219: 207: 206: 196: 149:Banach algebra 135: 134: 49: 47: 40: 26: 18:C star algebra 9: 6: 4: 3: 2: 5093: 5082: 5079: 5077: 5074: 5073: 5071: 5056: 5048: 5047: 5044: 5038: 5035: 5033: 5030: 5028: 5027:Weak topology 5025: 5023: 5020: 5018: 5015: 5013: 5010: 5009: 5007: 5003: 4996: 4992: 4989: 4987: 4984: 4982: 4979: 4977: 4974: 4972: 4969: 4967: 4964: 4962: 4959: 4957: 4954: 4952: 4951:Index theorem 4949: 4947: 4944: 4942: 4939: 4937: 4934: 4933: 4931: 4927: 4921: 4918: 4916: 4913: 4912: 4910: 4908:Open problems 4906: 4900: 4897: 4895: 4892: 4890: 4887: 4885: 4882: 4880: 4877: 4875: 4872: 4871: 4869: 4865: 4859: 4856: 4854: 4851: 4849: 4846: 4844: 4841: 4839: 4836: 4834: 4831: 4829: 4826: 4824: 4821: 4819: 4816: 4814: 4811: 4810: 4808: 4804: 4798: 4795: 4793: 4790: 4788: 4785: 4783: 4780: 4778: 4775: 4773: 4770: 4768: 4765: 4763: 4760: 4758: 4755: 4754: 4752: 4750: 4746: 4736: 4733: 4731: 4728: 4726: 4723: 4720: 4716: 4712: 4709: 4707: 4704: 4702: 4699: 4698: 4696: 4692: 4686: 4683: 4681: 4678: 4676: 4673: 4671: 4668: 4666: 4663: 4661: 4658: 4656: 4653: 4651: 4648: 4646: 4643: 4641: 4638: 4637: 4634: 4631: 4627: 4622: 4618: 4614: 4607: 4602: 4600: 4595: 4593: 4588: 4587: 4584: 4572: 4569: 4567: 4564: 4562: 4559: 4557: 4554: 4552: 4549: 4547: 4544: 4542: 4539: 4537: 4534: 4532: 4529: 4527: 4524: 4522: 4519: 4517: 4514: 4512: 4509: 4507: 4504: 4502: 4499: 4496: 4492: 4489: 4487: 4484: 4482: 4479: 4478: 4476: 4472: 4466: 4463: 4462: 4460: 4456: 4450: 4447: 4445: 4442: 4440: 4437: 4435: 4432: 4430: 4427: 4425: 4422: 4420: 4417: 4415: 4412: 4410: 4407: 4406: 4404: 4402:Miscellaneous 4400: 4393: 4389: 4386: 4384: 4381: 4379: 4376: 4374: 4371: 4370: 4368: 4364: 4358: 4355: 4353: 4350: 4348: 4345: 4343: 4340: 4339: 4337: 4333: 4325: 4322: 4321: 4320: 4317: 4315: 4312: 4310: 4307: 4305: 4302: 4300: 4297: 4295: 4291: 4289: 4286: 4285: 4283: 4279: 4273: 4270: 4268: 4265: 4263: 4260: 4258: 4255: 4253: 4250: 4248: 4245: 4243: 4240: 4238: 4235: 4233: 4230: 4229: 4227: 4223: 4217: 4214: 4212: 4209: 4207: 4204: 4202: 4199: 4197: 4194: 4190: 4187: 4185: 4182: 4180: 4177: 4176: 4175: 4172: 4171: 4169: 4167:Decomposition 4165: 4159: 4156: 4154: 4151: 4149: 4146: 4144: 4141: 4139: 4136: 4134: 4131: 4130: 4128: 4126: 4122: 4116: 4113: 4111: 4108: 4105: 4103: 4100: 4097: 4095: 4092: 4089: 4087: 4084: 4083: 4081: 4077: 4071: 4068: 4066: 4063: 4061: 4058: 4056: 4053: 4051: 4048: 4046: 4043: 4041: 4038: 4037: 4035: 4031: 4025: 4022: 4020: 4017: 4015: 4012: 4010: 4007: 4005: 4002: 4000: 3997: 3995: 3992: 3990: 3987: 3985: 3982: 3980: 3977: 3976: 3974: 3970: 3966: 3962: 3955: 3950: 3948: 3943: 3941: 3936: 3935: 3932: 3923: 3918: 3914: 3910: 3906: 3905:Segal, Irving 3902: 3898: 3896:3-540-63633-1 3892: 3888: 3884: 3880: 3877: 3873: 3872: 3867: 3862: 3858: 3856:0-471-23900-3 3852: 3848: 3843: 3839: 3833: 3830:, CRC Press, 3829: 3825: 3821: 3817: 3815:0-7204-0762-1 3811: 3806: 3805: 3799: 3795: 3791: 3789:0-12-185860-X 3785: 3780: 3779: 3773: 3772:Connes, Alain 3769: 3766: 3761: 3759:0-387-90176-0 3755: 3751: 3747: 3743: 3742: 3730: 3724: 3717: 3712: 3706: 3701: 3694: 3691:, p. 6, 3690: 3685: 3678: 3674: 3669: 3665: 3655: 3652: 3650: 3647: 3644: 3641: 3639: 3636: 3634: 3631: 3629: 3626: 3624: 3621: 3619: 3616: 3615: 3609: 3607: 3603: 3598: 3596: 3592: 3588: 3584: 3580: 3576: 3572: 3568: 3564: 3560: 3556: 3552: 3548: 3544: 3540: 3536: 3532: 3522: 3520: 3515: 3513: 3508: 3506: 3502: 3498: 3494: 3490: 3487:A C*-algebra 3480: 3478: 3473: 3471: 3467: 3458: 3456: 3452: 3448: 3444: 3440: 3436: 3432: 3431:group algebra 3428: 3425: 3420: 3418: 3414: 3410: 3406: 3401: 3397: 3391: 3387: 3383: 3379: 3375: 3371: 3367: 3363: 3353: 3351: 3347: 3343: 3327: 3307: 3284: 3276: 3272: 3263: 3244: 3236: 3232: 3223: 3219: 3203: 3180: 3172: 3168: 3159: 3154: 3135: 3131: 3119: 3103: 3081: 3077: 3056: 3036: 3013: 3005: 3001: 2992: 2973: 2965: 2961: 2940: 2917: 2909: 2905: 2881: 2873: 2869: 2860: 2856: 2852: 2833: 2825: 2821: 2812: 2808: 2798: 2796: 2792: 2788: 2784: 2780: 2776: 2772: 2768: 2764: 2760: 2756: 2754: 2750: 2745: 2740: 2733: 2726: 2719: 2715: 2711: 2707: 2700: 2696: 2692: 2688: 2684: 2680: 2676: 2672: 2668: 2664: 2658: 2656: 2649: 2642: 2638: 2616: 2608: 2604: 2597: 2592: 2589: 2586: 2582: 2578: 2575: 2568: 2567: 2566: 2563: 2559: 2554: 2547: 2543: 2539: 2535: 2530: 2527: 2525: 2521: 2517: 2513: 2509: 2505: 2501: 2497: 2493: 2483: 2481: 2477: 2473: 2469: 2465: 2461: 2457: 2453: 2449: 2445: 2441: 2438: 2437:Hilbert space 2434: 2430: 2420: 2418: 2413: 2411: 2407: 2403: 2399: 2395: 2391: 2387: 2382: 2380: 2373: 2369: 2368:positive cone 2365: 2361: 2357: 2352: 2347: 2343: 2339: 2335: 2331: 2325: 2323: 2319: 2300: 2297: 2292: 2286: 2283: 2279: 2275: 2272: 2265: 2264: 2263: 2261: 2257: 2253: 2248: 2246: 2242: 2238: 2234: 2230: 2229:operator norm 2226: 2222: 2218: 2215: 2211: 2207: 2203: 2188: 2185: 2183: 2179: 2171: 2167: 2163: 2159: 2158: 2153: 2149: 2145: 2141: 2137: 2136: 2119: 2116: 2113: 2110: 2099: 2096: 2091: 2087: 2083: 2078: 2074: 2070: 2067: 2060: 2046: 2038: 2034: 2030: 2023: 2022: 2021: 2020: 2019: 2017: 2006: 2002: 1998: 1988: 1986: 1982: 1978: 1974: 1969: 1955: 1952: 1949: 1946: 1943: 1923: 1920: 1917: 1909: 1893: 1873: 1853: 1850: 1847: 1827: 1822: 1818: 1814: 1811: 1791: 1783: 1767: 1764: 1761: 1741: 1738: 1735: 1715: 1707: 1704: 1700: 1695: 1671: 1667: 1649: 1645: 1641: 1633: 1617: 1612: 1608: 1599: 1581: 1577: 1573: 1570: 1556: 1554: 1550: 1540: 1538: 1534: 1530: 1526: 1521: 1502: 1498: 1491: 1485: 1457: 1453: 1443: 1437: 1429: 1425: 1421: 1393: 1389: 1382: 1376: 1361: 1343: 1335: 1329: 1321: 1317: 1313: 1303: 1302: 1301: 1299: 1295: 1294:C. E. Rickart 1285: 1283: 1279: 1275: 1271: 1267: 1262: 1260: 1256: 1252: 1228: 1220: 1214: 1211: 1203: 1199: 1192: 1185: 1184: 1183: 1182: 1179: 1175: 1171: 1170: 1149: 1143: 1137: 1131: 1128: 1122: 1119: 1113: 1106: 1105: 1104: 1103: 1100: 1096: 1092: 1088: 1087: 1086: 1084: 1080: 1076: 1072: 1068: 1064: 1060: 1039: 1028: 1024: 1021: 1018: 1013: 1009: 1005: 997: 983: 977: 972: 968: 961: 956: 948: 938: 937: 936: 935: 934: 932: 927: 925: 920: 907: 902: 894: 888: 880: 876: 872: 861: 859: 855: 851: 847: 827: 819: 815: 805: 799: 793: 788: 784: 773: 772: 771: 770: 766: 762: 758: 757: 740: 735: 731: 722: 717: 712: 704: 701: 691: 690: 689: 688: 684: 680: 659: 656: 648: 647: 628: 624: 618: 614: 610: 605: 597: 594: 584: 568: 564: 560: 555: 551: 547: 542: 534: 531: 528: 518: 517: 516: 515: 511: 507: 503: 499: 498: 481: 478: 473: 463: 459: 452: 447: 444: 440: 432: 431: 430: 429: 425: 421: 417: 413: 412: 411: 397: 394: 391: 369: 365: 358: 351: 347: 343: 339: 334: 326: 324: 320: 316: 311: 309: 305: 300: 298: 294: 290: 286: 282: 278: 274: 270: 266: 261: 259: 256: 252: 248: 229: 221: 217: 205:of operators. 204: 200: 197: 195:of operators. 194: 193:norm topology 190: 186: 183: 182: 181: 179: 178:Hilbert space 176: 172: 168: 165: 162: 158: 154: 150: 146: 142: 131: 128: 120: 117:February 2013 109: 106: 102: 99: 95: 92: 88: 85: 81: 78: â€“  77: 73: 72:Find sources: 66: 62: 56: 55: 50:This article 48: 44: 39: 38: 33: 19: 5017:Balanced set 4991:Distribution 4929:Applications 4878: 4782:Krein–Milman 4767:Closed graph 4474:Applications 4304:Disk algebra 4158:Spectral gap 4033:Main results 3993: 3915:(2): 73–88, 3912: 3908: 3889:, Springer, 3886: 3869: 3866:"C*-algebra" 3846: 3827: 3803: 3777: 3749: 3728: 3723: 3718:, p. 75 3711: 3700: 3693:Google Books 3684: 3677:Google Books 3668: 3599: 3594: 3590: 3586: 3582: 3578: 3574: 3570: 3566: 3562: 3558: 3554: 3550: 3546: 3542: 3538: 3534: 3528: 3516: 3509: 3504: 3500: 3496: 3492: 3488: 3486: 3474: 3464: 3450: 3449:in the case 3446: 3438: 3434: 3426: 3421: 3416: 3412: 3408: 3404: 3399: 3395: 3385: 3381: 3377: 3373: 3369: 3361: 3359: 3342:homeomorphic 3155: 2854: 2850: 2806: 2804: 2790: 2786: 2782: 2778: 2770: 2766: 2762: 2758: 2757: 2752: 2748: 2743: 2735: 2728: 2721: 2717: 2713: 2709: 2702: 2698: 2694: 2690: 2686: 2682: 2678: 2674: 2666: 2662: 2660: 2651: 2644: 2640: 2633: 2631: 2561: 2557: 2549: 2545: 2541: 2537: 2533: 2532: 2528: 2523: 2519: 2511: 2503: 2499: 2491: 2489: 2475: 2471: 2467: 2463: 2459: 2455: 2451: 2446:denotes the 2443: 2439: 2428: 2426: 2414: 2389: 2385: 2383: 2378: 2371: 2359: 2355: 2350: 2345: 2341: 2337: 2333: 2329: 2327: 2321: 2317: 2315: 2255: 2251: 2250: 2224: 2220: 2213: 2209: 2205: 2201: 2199: 2186: 2175: 2169: 2168:is dense in 2165: 2161: 2155: 2151: 2147: 2143: 2139: 2015: 2004: 1996: 1994: 1970: 1907: 1706:vector space 1698: 1696: 1669: 1666:non-negative 1665: 1600:of the form 1597: 1562: 1546: 1536: 1532: 1528: 1522: 1365: 1359: 1291: 1281: 1277: 1273: 1269: 1268:is called a 1265: 1263: 1250: 1248: 1177: 1173: 1098: 1094: 1090: 1082: 1081:is called a 1078: 1074: 1070: 1066: 1062: 1056: 928: 921: 862: 857: 849: 845: 844: 764: 760: 682: 678: 509: 505: 501: 423: 419: 418:, for every 337: 335: 332: 312: 308:Mark Naimark 301: 262: 250: 246: 208: 198: 184: 166: 144: 138: 123: 114: 104: 97: 90: 83: 76:"C*-algebra" 71: 59:Please help 54:verification 51: 5076:C*-algebras 4946:Heat kernel 4936:Hardy space 4843:Trace class 4757:Hahn–Banach 4719:Topological 4501:Heat kernel 4201:Compression 4086:Isospectral 3746:Arveson, W. 3555:observables 3519:James Glimm 3514:is type I. 2516:norm closed 2260:canonically 2237:direct sums 2154:contains a 1632:convex cone 1525:I. E. Segal 1255:contractive 858:C* identity 273:observables 5070:Categories 4879:C*-algebra 4694:Properties 4179:Continuous 3994:C*-algebra 3989:B*-algebra 3739:References 3716:Segal 1947 3705:Segal 1947 3541:(elements 3388:) that is 3352:programs. 3262:isomorphic 3218:characters 2565:such that 2316:where min 2241:semisimple 2164:such that 2018:such that 1983:using the 1754:satisfies 1282:isomorphic 677:and every 416:involution 189:closed set 153:involution 87:newspapers 4853:Unbounded 4848:Transpose 4806:Operators 4735:Separable 4730:Reflexive 4715:Algebraic 4701:Barrelled 3965:-algebras 3883:Sakai, S. 3876:EMS Press 3628:*-algebra 3390:universal 2793:) is the 2650:) with || 2590:∈ 2583:⨁ 2579:≅ 2496:separable 2386:†-algebra 2377:group of 2287:∈ 2280:⨁ 2117:μ 2114:≤ 2111:λ 2097:≤ 2092:μ 2084:≤ 2079:λ 2071:≤ 2044:→ 2039:λ 1953:≥ 1947:− 1921:≥ 1851:∈ 1840:for some 1823:∗ 1765:≥ 1739:∈ 1716:≥ 1650:∗ 1613:∗ 1582:∗ 1508:‖ 1503:∗ 1495:‖ 1489:‖ 1483:‖ 1463:‖ 1458:∗ 1450:‖ 1447:‖ 1441:‖ 1435:‖ 1430:∗ 1419:‖ 1411:. Hence, 1399:‖ 1394:∗ 1386:‖ 1380:‖ 1374:‖ 1340:‖ 1333:‖ 1327:‖ 1322:∗ 1311:‖ 1259:isometric 1229:∗ 1215:π 1204:∗ 1193:π 1144:π 1132:π 1114:π 1025:λ 1022:− 1014:∗ 998:λ 981:‖ 973:∗ 965:‖ 953:‖ 946:‖ 899:‖ 892:‖ 886:‖ 881:∗ 870:‖ 854:*-algebra 825:‖ 820:∗ 812:‖ 809:‖ 803:‖ 797:‖ 789:∗ 781:‖ 736:∗ 726:¯ 723:λ 713:∗ 702:λ 660:∈ 657:λ 629:∗ 619:∗ 606:∗ 569:∗ 556:∗ 543:∗ 474:∗ 464:∗ 448:∗ 445:∗ 414:It is an 395:∈ 370:∗ 362:↦ 258:Hausdorff 145:C-algebra 5055:Category 4867:Algebras 4749:Theorems 4706:Complete 4675:Schwartz 4621:glossary 4566:Weyl law 4511:Lax pair 4458:Examples 4292:With an 4211:Discrete 4189:Residual 4125:Spectrum 4110:operator 4102:operator 4094:operator 4009:Spectrum 3885:(1971), 3800:(1969), 3774:(1994), 3748:(1976), 3612:See also 3364:with an 3196:, where 2775:quotient 2720:and let 2534:Theorem. 2454: : 2364:K-theory 2252:Theorem. 2217:matrices 2191:Examples 2178:quotient 2138:In case 1910:satisfy 1782:spectrum 1670:positive 1358:for all 1065: : 759:For all 500:For all 203:adjoints 4858:Unitary 4838:Nuclear 4823:Compact 4818:Bounded 4813:Adjoint 4787:Min–max 4680:Sobolev 4665:Nuclear 4655:Hilbert 4650:FrĂ©chet 4615: ( 4107:Unitary 3577:with φ( 2989:has an 2661:Though 2657:|| → 0. 2442:; here 2394:physics 2370:of the 1999:has an 924:history 846:Remark. 340:, is a 260:space. 191:in the 175:complex 164:algebra 161:complex 157:adjoint 101:scholar 4833:Normal 4670:Orlicz 4660:Hölder 4640:Banach 4629:Spaces 4617:topics 4091:Normal 3893:  3853:  3834:  3812:  3786:  3756:  3394:π ' : 2398:dagger 2247:type: 1977:states 103:  96:  89:  82:  74:  4645:Besov 4184:Point 3660:Notes 3559:state 3545:with 3380:into 2853:that 2809:be a 2785:) by 2514:is a 2506:) of 2494:be a 2258:, is 2219:over 2208:) of 2182:ideal 852:is a 293:rings 269:model 253:is a 173:on a 108:JSTOR 94:books 4993:(or 4711:Dual 4115:Unit 3963:and 3891:ISBN 3851:ISBN 3832:ISBN 3810:ISBN 3784:ISBN 3754:ISBN 3475:The 3348:and 3340:are 3320:and 3156:The 3069:let 2805:Let 2701:let 2673:for 2490:Let 2429:B(H) 1886:and 1276:and 1172:For 1093:and 1089:For 1077:and 384:for 306:and 143:, a 80:news 3917:doi 3597:). 3579:u*u 3565:(a 3529:In 3445:of 3433:of 3264:to 3260:is 2777:of 2755:). 2536:If 2510:on 2358:of 2336:), 2290:min 2166:hAh 2012:λ∈I 1936:if 1906:of 1784:of 1176:in 1097:in 1085:if 987:sup 763:in 681:in 508:in 422:in 350:map 317:of 279:'s 267:to 169:of 63:by 5072:: 4619:– 3913:53 3911:, 3874:, 3868:, 3782:, 3585:∈ 3573:→ 3549:= 3547:x* 3457:. 3419:. 3398:→ 2797:. 2716:≄ 2693:= 2482:. 2458:→ 2444:x* 2419:. 2412:. 2384:A 2381:. 2348:)} 2330:Ae 2212:× 2204:, 1987:. 1968:. 1694:) 1555:. 1284:. 1069:→ 1061:, 1057:A 504:, 325:. 299:. 4997:) 4721:) 4717:/ 4713:( 4623:) 4605:e 4598:t 4591:v 4497:) 4493:( 4394:) 4390:( 3953:e 3946:t 3939:v 3926:. 3919:: 3900:. 3841:. 3767:. 3695:. 3679:. 3595:x 3591:x 3587:A 3583:u 3575:C 3571:A 3567:C 3563:A 3551:x 3543:x 3539:A 3535:A 3505:A 3501:A 3497:A 3493:A 3489:A 3451:G 3447:G 3439:G 3435:G 3427:G 3417:A 3409:A 3407:( 3405:E 3400:B 3396:A 3386:A 3384:( 3382:E 3378:A 3374:A 3372:( 3370:E 3362:A 3328:Y 3308:X 3288:) 3285:Y 3282:( 3277:0 3273:C 3248:) 3245:X 3242:( 3237:0 3233:C 3204:X 3184:) 3181:X 3178:( 3173:0 3169:C 3141:} 3136:K 3132:f 3128:{ 3104:K 3082:K 3078:f 3057:K 3037:X 3017:) 3014:X 3011:( 3006:0 3002:C 2977:) 2974:X 2971:( 2966:0 2962:C 2941:X 2921:) 2918:X 2915:( 2910:0 2906:C 2885:) 2882:X 2879:( 2874:0 2870:C 2851:X 2837:) 2834:X 2831:( 2826:0 2822:C 2807:X 2791:H 2789:( 2787:K 2783:H 2781:( 2779:B 2771:H 2769:( 2767:B 2763:H 2761:( 2759:K 2753:H 2751:( 2749:K 2744:n 2741:} 2738:n 2736:e 2731:n 2729:H 2724:n 2722:e 2718:n 2714:k 2710:l 2705:n 2703:H 2699:n 2695:l 2691:H 2687:l 2683:H 2679:H 2677:( 2675:K 2667:H 2665:( 2663:K 2654:i 2652:T 2647:i 2645:H 2643:( 2641:K 2636:i 2634:T 2617:, 2614:) 2609:i 2605:H 2601:( 2598:K 2593:I 2587:i 2576:A 2562:I 2560:∈ 2558:i 2555:} 2552:i 2550:H 2546:H 2544:( 2542:K 2538:A 2524:H 2522:( 2520:B 2512:H 2504:H 2502:( 2500:K 2492:H 2476:H 2472:H 2470:( 2468:B 2464:A 2460:H 2456:H 2452:x 2440:H 2379:A 2375:0 2372:K 2360:A 2351:e 2346:e 2342:A 2338:C 2334:e 2324:. 2322:A 2318:A 2301:e 2298:A 2293:A 2284:e 2276:= 2273:A 2256:A 2225:C 2221:C 2214:n 2210:n 2206:C 2202:n 2172:. 2170:A 2162:h 2152:A 2148:A 2144:A 2140:A 2120:. 2100:1 2088:e 2075:e 2068:0 2047:x 2035:e 2031:x 2016:A 2010:} 2008:λ 2005:e 1997:A 1956:0 1950:y 1944:x 1924:y 1918:x 1908:A 1894:y 1874:x 1854:A 1848:s 1828:s 1819:s 1815:= 1812:x 1792:x 1768:0 1762:x 1742:A 1736:x 1699:A 1681:R 1646:x 1642:x 1618:x 1609:x 1598:A 1578:x 1574:= 1571:x 1537:H 1533:H 1531:( 1529:B 1499:x 1492:= 1486:x 1454:x 1444:x 1438:= 1426:x 1422:x 1390:x 1383:= 1377:x 1360:x 1344:2 1336:x 1330:= 1318:x 1314:x 1278:B 1274:A 1266:π 1251:π 1225:) 1221:x 1218:( 1212:= 1209:) 1200:x 1196:( 1178:A 1174:x 1153:) 1150:y 1147:( 1141:) 1138:x 1135:( 1129:= 1126:) 1123:y 1120:x 1117:( 1099:A 1095:y 1091:x 1079:B 1075:A 1071:B 1067:A 1063:π 1040:. 1037:} 1029:1 1019:x 1010:x 1006:: 1002:| 994:| 990:{ 984:= 978:x 969:x 962:= 957:2 949:x 908:, 903:2 895:x 889:= 877:x 873:x 850:A 828:. 816:x 806:x 800:= 794:x 785:x 767:: 765:A 761:x 741:. 732:x 718:= 709:) 705:x 699:( 685:: 683:A 679:x 664:C 625:x 615:y 611:= 602:) 598:y 595:x 592:( 565:y 561:+ 552:x 548:= 539:) 535:y 532:+ 529:x 526:( 512:: 510:A 506:y 502:x 482:x 479:= 470:) 460:x 456:( 453:= 441:x 426:: 424:A 420:x 398:A 392:x 366:x 359:x 338:A 251:X 247:X 233:) 230:X 227:( 222:0 218:C 199:A 185:A 167:A 130:) 124:( 119:) 115:( 105:· 98:· 91:· 84:· 57:. 34:. 20:)

Index

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characteristic velocity

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functional analysis
Banach algebra
involution
adjoint
complex
algebra
continuous linear operators
complex
Hilbert space
closed set
norm topology
adjoints
locally compact
Hausdorff
quantum mechanics
model
observables

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