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Countable set

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1288:, has infinitely many elements, and we cannot use any natural number to give its size. It might seem natural to divide the sets into different classes: put all the sets containing one element together; all the sets containing two elements together; ...; finally, put together all infinite sets and consider them as having the same size. This view works well for countably infinite sets and was the prevailing assumption before Georg Cantor's work. For example, there are infinitely many odd integers, infinitely many even integers, and also infinitely many integers overall. We can consider all these sets to have the same "size" because we can arrange things such that, for every integer, there is a distinct even integer: 3945: 3457: 1102: 10097: 7630: 3940:{\displaystyle {\begin{array}{c|c|c }{\text{Index}}&{\text{Tuple}}&{\text{Element}}\\\hline 0&(0,0)&{\textbf {a}}_{0}\\1&(0,1)&{\textbf {a}}_{1}\\2&(1,0)&{\textbf {b}}_{0}\\3&(0,2)&{\textbf {a}}_{2}\\4&(1,1)&{\textbf {b}}_{1}\\5&(2,0)&{\textbf {c}}_{0}\\6&(0,3)&{\textbf {a}}_{3}\\7&(1,2)&{\textbf {b}}_{2}\\8&(2,1)&{\textbf {c}}_{1}\\9&(3,0)&{\textbf {d}}_{0}\\10&(0,4)&{\textbf {a}}_{4}\\\vdots &&\end{array}}} 10167: 7618: 2172: 2230: 8339: 3397: 1000:, called roster form. This is only effective for small sets, however; for larger sets, this would be time-consuming and error-prone. Instead of listing every single element, sometimes an ellipsis ("...") is used to represent many elements between the starting element and the end element in a set, if the writer believes that the reader can easily guess what ... represents; for example, 2002: 2433: 2167:{\displaystyle {\begin{matrix}0\leftrightarrow 1,&1\leftrightarrow 2,&2\leftrightarrow 3,&3\leftrightarrow 4,&4\leftrightarrow 5,&\ldots \\0\leftrightarrow 0,&1\leftrightarrow 2,&2\leftrightarrow 4,&3\leftrightarrow 6,&4\leftrightarrow 8,&\ldots \end{matrix}}} 7215:
Cantor's discovery of uncountable sets in 1874 was one of the most unexpected events in the history of mathematics. Before 1874, infinity was not even considered a legitimate mathematical subject by most people, so the need to distinguish between countable and uncountable infinities could not have
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showed that not all infinite sets are countably infinite. For example, the real numbers cannot be put into one-to-one correspondence with the natural numbers (non-negative integers). The set of real numbers has a greater cardinality than the set of natural numbers and is said to be uncountable.
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that maps between two sets such that each element of each set corresponds to a single element in the other set. This mathematical notion of "size", cardinality, is that two sets are of the same size if and only if there is a bijection between them. We call all sets that are in one-to-one
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This set is the union of the length-1 sequences, the length-2 sequences, the length-3 sequences, each of which is a countable set (finite Cartesian product). So we are talking about a countable union of countable sets, which is countable by the previous theorem.
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from it into the natural numbers; this means that each element in the set may be associated to a unique natural number, or that the elements of the set can be counted one at a time, although the counting may never finish due to an infinite number of elements.
5851: 2927:-tuples made by the Cartesian product of finitely many different sets, each element in each tuple has the correspondence to a natural number, so every tuple can be written in natural numbers then the same logic is applied to prove the theorem. 1291: 3377:
With the foresight of knowing that there are uncountable sets, we can wonder whether or not this last result can be pushed any further. The answer is "yes" and "no", we can extend it, but we need to assume a new axiom to do so.
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is uncountable, thus showing that not all infinite sets are countable. In 1878, he used one-to-one correspondences to define and compare cardinalities. In 1883, he extended the natural numbers with his infinite
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are integers), then for every positive fraction, we can come up with a distinct natural number corresponding to it. This representation also includes the natural numbers, since every natural number
4709: 2542: 5674:-th root of the polynomial, where the roots are sorted by absolute value from small to big, then sorted by argument from small to big. We can define an injection (i. e. one-to-one) function 5466: 5056: 4759: 2224: 5708: 5182: 1591: 4435: 6073: 6838: 6632: 2428:{\displaystyle 0\leftrightarrow (0,0),1\leftrightarrow (1,0),2\leftrightarrow (0,1),3\leftrightarrow (2,0),4\leftrightarrow (1,1),5\leftrightarrow (0,2),6\leftrightarrow (3,0),\ldots } 784: 4864: 1286: 2174:
Every countably infinite set is countable, and every infinite countable set is countably infinite. Furthermore, any subset of the natural numbers is countable, and more generally:
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The elements of any finite subset can be ordered into a finite sequence. There are only countably many finite sequences, so also there are only countably many finite subsets.
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can be used to show that this minimal model is countable. The fact that the notion of "uncountability" makes sense even in this model, and in particular that this model
5108: 5082: 2767: 2691: 1733: 998: 6758: 6592: 4203: 4128: 1938:, the set of even integers. We can show these sets are countably infinite by exhibiting a bijection to the natural numbers. This can be achieved using the assignments 5652: 5520: 3101: 2647: 864: 6429: 6380: 5941: 5878: 3357: 2863: 2831: 2799: 2723: 2569: 838: 811: 3325: 3149: 3055: 1596: 578: 219: 6858: 6798: 6778: 6692: 6672: 6652: 6526: 6331: 6025: 5961: 5898: 5672: 5309: 5244: 4904: 4884: 4353: 4333: 4276: 4243: 4223: 4168: 4148: 4092: 4072: 3293: 3273: 3253: 3233: 3121: 3075: 2925: 2883: 2609: 2589: 2460: 1804: 1780: 1757: 1536: 1508: 1224: 1171: 1151: 1131: 1096: 1076: 884: 725: 676: 632: 537: 463: 419: 392: 346: 302: 178: 962:, and may be described in many ways. One way is simply to list all of its elements; for example, the set consisting of the integers 3, 4, and 5 may be denoted 8476: 6078: 148:
may also be used, e.g. referring to countable and countably infinite respectively, definitions vary and care is needed respecting the difference with
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Although the terms "countable" and "countably infinite" as defined here are quite common, the terminology is not universal. An alternative style uses
1393:{\displaystyle \ldots \,-\!2\!\rightarrow \!-\!4,\,-\!1\!\rightarrow \!-\!2,\,0\!\rightarrow \!0,\,1\!\rightarrow \!2,\,2\!\rightarrow \!4\,\cdots } 3454:, we first assign each element of each set a tuple, then we assign each tuple an index using a variant of the triangular enumeration we saw above: 5502:
Per definition, every algebraic number (including complex numbers) is a root of a polynomial with integer coefficients. Given an algebraic number
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to list all the elements, because the number of elements in the set is finite. If we number the elements of the set 1, 2, and so on, up to
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is countable. This result generalizes to the Cartesian product of any finite collection of countable sets and the proof follows by
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Invitation To Algebra: A Resource Compendium For Teachers, Advanced Undergraduate Students And Graduate Students In Mathematics
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is injective. It then follows that the Cartesian product of any two countable sets is countable, because if
4808: 4446: 4711:, it makes no difference whether one considers 0 a natural number or not. In any case, this article follows 1229: 10636: 9980: 9806: 9492: 9126: 8725: 7655: 7584:. Texts and Readings in Mathematics. Vol. 37 (Third ed.). Singapore: Springer. pp. 181–210. 6201: 1941: 1885: 1003: 10629: 10267: 10230: 9858: 9853: 9463: 9202: 9131: 8460: 8361: 7811: 6697: 6531: 4943: 4909: 1973: 6229: 1831: 472: 9787: 9377: 8771: 8739: 8430: 7608: 5846:{\displaystyle f(\alpha )=2^{k-1}\cdot 3^{a_{0}}\cdot 5^{a_{1}}\cdot 7^{a_{2}}\cdots {p_{n+2}}^{a_{n}}} 4358: 4281: 47: 10284: 5966: 10779: 10318: 10210: 10198: 10193: 10077: 10026: 9923: 9421: 9382: 8859: 8504: 8219: 8175: 6310: 6144: 3950: 3389: 1403: 91: 71: 8533: 7817: 6284: 5380: 944:, and used sets of ordinals to produce an infinity of sets having different infinite cardinalities. 10126: 9918: 9848: 9387: 9239: 9222: 8945: 8425: 8342: 8214: 8134: 8057: 8018: 7980: 7952: 7924: 7896: 7784: 7751: 7723: 7695: 6385: 6336: 5471: 5314: 5129: 4633: 3185: 3163: 2998: 2976: 2951: 2888: 1809: 685: 637: 424: 355: 307: 258: 10738: 10656: 10531: 10483: 10297: 10220: 9750: 9727: 9688: 9574: 9515: 9161: 9081: 8925: 8869: 8482: 7648: 5249: 2234: 1652: 1451: 1176: 899: 583: 224: 7577: 5187: 10690: 10571: 10383: 10203: 10040: 9767: 9745: 9712: 9605: 9451: 9436: 9409: 9360: 9244: 9179: 9004: 8970: 8965: 8839: 8670: 8647: 7415: 5111: 5087: 5061: 4473: 2728: 2652: 1700: 1440: 965: 679: 7341: 7075: 7048: 6731: 6565: 4176: 4101: 10606: 10576: 10520: 10440: 10420: 10398: 9970: 9823: 9615: 9333: 9069: 8975: 8834: 8819: 8700: 8675: 8287: 8123: 7246: 7198: 7105: 7016: 6989: 6899: 5637: 5505: 4515: 3080: 2614: 1101: 843: 7156: 10680: 10670: 10504: 10435: 10388: 10328: 10215: 9943: 9905: 9782: 9586: 9426: 9350: 9328: 9156: 9114: 9013: 8980: 8844: 8632: 8543: 8040: 7773: 6407: 6358: 5919: 5856: 3330: 2836: 2804: 2772: 2696: 2547: 1429:(see picture). What we have done here is arrange the integers and the even integers into a 816: 789: 8: 10675: 10586: 10494: 10489: 10303: 10245: 10183: 10119: 10072: 9963: 9948: 9928: 9885: 9772: 9722: 9648: 9593: 9530: 9323: 9318: 9266: 9034: 9023: 8695: 8595: 8523: 8514: 8510: 8445: 8440: 8251: 8161: 8118: 8100: 7878: 4580:. This is the key definition that determines whether a total order is also a well order. 4504: 4389: 4254: 3302: 3126: 3032: 553: 349: 194: 4250:
These follow from the definitions of countable set as injective / surjective functions.
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is countably infinite, as can be seen by following a path like the one in the picture:
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The usual order of rational numbers (Cannot be explicitly written as an ordered list!)
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can easily be one-to-one mapped to the set of natural number pairs (2-tuples) because
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is one-to-one mapped to the set of natural numbers. For example, the set of positive
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Labyrinth of Thought: A History of Set Theory and Its Role in Mathematical Thought
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is any integer that can be specified. (No matter how large the specified integer
253: 114: 40: 7589: 10748: 10545: 10526: 10430: 10415: 10372: 10308: 10250: 10016: 9995: 9953: 9933: 9828: 9683: 9281: 9271: 9261: 9256: 9190: 9064: 8940: 8829: 8824: 8802: 8403: 8256: 8246: 8231: 8050: 7918: 7689: 7371: 7194: 4538: 941: 75: 6496:, rather than an injection, there is no requirement that the sets be disjoint. 10768: 10753: 10555: 10464: 9990: 9668: 9175: 8960: 8950: 8920: 8575: 8319: 8292: 8201: 7376: 10723: 1642:{\displaystyle a\leftrightarrow 1,\ b\leftrightarrow 2,\ c\leftrightarrow 3} 10703: 10698: 10516: 10445: 10403: 10262: 10166: 9890: 9737: 9638: 9630: 9510: 9458: 9367: 9303: 9286: 9217: 9076: 8935: 8637: 8420: 8282: 8084: 7555: 6489:{\displaystyle G:\mathbf {N} \times \mathbf {N} \to \bigcup _{i\in I}A_{i}} 5901: 4589: 4392:. As an immediate consequence of this and the Basic Theorem above we have: 2189: 1478: 542: 110: 10728: 10363: 10000: 9880: 9059: 9049: 8996: 8680: 8600: 8585: 8465: 8410: 8108: 7890: 7513: 7482: 4527: 4469: 4453: 4438: 3235:
to be shown as countable is one-to-one mapped (injection) to another set
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are natural numbers, by repeatedly mapping the first two elements of an
10708: 10479: 10142: 8930: 8785: 8756: 8562: 8089: 7946: 7534: 4534: 466: 249: 67: 36: 32: 5021:{\displaystyle f\times g:\mathbb {N} \times \mathbb {N} \to A\times B} 10511: 10474: 10425: 10323: 10082: 9985: 9038: 8955: 8915: 8879: 8815: 8627: 8617: 8590: 8353: 7382:, Calculus, vol. 2 (2nd ed.), New York: John Wiley + Sons, 4761:
is countable as a consequence of the definition because the function
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is countable. Similarly we can show all finite sets are countable.
117:, that is, sets that are not countable; for example the set of the 7501:(Springer-Verlag edition). Reprinted by Martino Fine Books, 2011. 2229: 9663: 8455: 7717: 7640: 6134:{\displaystyle G:I\times \mathbf {N} \to \bigcup _{i\in I}A_{i},} 5370:{\displaystyle g:\mathbb {Z} \times \mathbb {N} \to \mathbb {Q} } 4798:{\displaystyle f:\mathbb {N} \times \mathbb {N} \to \mathbb {N} } 4472:) of ZFC set theory, then there is a minimal standard model (see 2946: 1879: 1226:
elements.) For example, the set of natural numbers, denotable by
1051: 4000:{\displaystyle {\textbf {a}},{\textbf {b}},{\textbf {c}},\dots } 3447:{\displaystyle {\textbf {a}},{\textbf {b}},{\textbf {c}},\dots } 3396: 10536: 10358: 7671: 7343:
Introduction to Set Theory, Third Edition, Revised and Expanded
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The usual order of integers (..., −3, −2, −1, 0, 1, 2, 3, ...)
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maps to 39. Since a different 2-tuple, that is a pair such as
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was seen as paradoxical in the early days of set theory; see
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if it is not countable, i.e. its cardinality is greater than
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Multi-Variable Calculus and Linear Algebra with Applications
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is negative, is an injective function. The rational numbers
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The integers in the order (0, 1, 2, 3, ...; −1, −2, −3, ...)
2007: 31:"Countable" redirects here. For the linguistic concept, see 4463: 3392:) The union of countably many countable sets is countable. 7104:
Katzourakis, Nikolaos; Varvaruca, Eugen (2 January 2018).
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The usual order of natural numbers (0, 1, 2, 3, 4, 5, ...)
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assigns one natural number to each pair of natural numbers
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In both examples of well orders here, any subset has a
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from 1 to 100. Even in this case, however, it is still
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Roads to Infinity: The Mathematics of Truth and Proof
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Dlab, Vlastimil; Williams, Kenneth S. (9 June 2020).
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vice versa, this defines a bijection, and shows that
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be a polynomial with integer coefficients such that
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There is an injective and surjective (and therefore
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to mean what is here called countably infinite, and
8145: 8068: 8029: 7991: 7963: 7935: 7907: 7830: 7795: 7762: 7734: 7706: 7375: 6852: 6832: 6792: 6772: 6752: 6720: 6686: 6666: 6646: 6626: 6586: 6554: 6520: 6488: 6423: 6396: 6382:from the non-empty collection of surjections from 6374: 6347: 6325: 6301: 6261: 6218: 6190: 6133: 6067: 6019: 5999: 5955: 5935: 5892: 5872: 5845: 5702: 5666: 5646: 5626: 5514: 5482: 5460: 5430: 5369: 5325: 5303: 5283: 5238: 5218: 5176: 5140: 5102: 5076: 5050: 5020: 4966: 4932: 4898: 4878: 4858: 4797: 4753: 4703: 4644: 4456:is uncountable, and so is the set of all infinite 4429: 4380: 4347: 4327: 4303: 4270: 4237: 4217: 4197: 4162: 4142: 4122: 4086: 4066: 3999: 3939: 3446: 3400:Enumeration for countable number of countable sets 3351: 3319: 3287: 3267: 3247: 3227: 3196: 3174: 3143: 3115: 3095: 3069: 3049: 3009: 2987: 2962: 2919: 2899: 2877: 2857: 2825: 2793: 2761: 2717: 2685: 2641: 2603: 2583: 2563: 2536: 2454: 2427: 2218: 2166: 1991: 1962: 1930: 1870: 1820: 1798: 1774: 1751: 1727: 1685: 1641: 1585: 1530: 1502: 1467: 1421: 1392: 1280: 1218: 1198: 1165: 1145: 1125: 1090: 1070: 1042: 992: 915: 878: 858: 832: 805: 778: 719: 696: 670: 648: 626: 599: 572: 531: 504: 457: 435: 413: 386: 366: 340: 318: 296: 269: 240: 213: 172: 4704:{\displaystyle \mathbb {N} ^{*}=\{1,2,3,\dots \}} 3215:Sometimes more than one mapping is useful: a set 3204:(the set of all rational numbers) are countable. 1382: 1378: 1367: 1363: 1352: 1348: 1337: 1333: 1329: 1325: 1314: 1310: 1306: 1302: 10766: 4468:If there is a set that is a standard model (see 2537:{\displaystyle (a_{1},a_{2},a_{3},\dots ,a_{n})} 7420:Journal fĂŒr die Reine und Angewandte Mathematik 7107:An Illustrative Introduction to Modern Analysis 5461:{\displaystyle \mathbb {Z} \times \mathbb {N} } 5051:{\displaystyle \mathbb {N} \times \mathbb {N} } 4754:{\displaystyle \mathbb {N} \times \mathbb {N} } 2219:{\displaystyle \mathbb {N} \times \mathbb {N} } 7493:Reprinted by Springer-Verlag, New York, 1974. 7099: 7097: 5703:{\displaystyle f:\mathbb {A} \to \mathbb {Q} } 5177:{\displaystyle f:\mathbb {Z} \to \mathbb {N} } 2941:of finitely many countable sets is countable. 1105:Bijective mapping from integer to even numbers 10127: 8369: 7656: 7463: 7340:Hrbacek, Karel; Jech, Thomas (22 June 1999). 7327: 6528:is countable there is an injective function 4906:are two countable sets there are surjections 1586:{\displaystyle \mathbb {N} =\{0,1,2,\dots \}} 7154: 5994: 5976: 4698: 4674: 4510:The minimal standard model includes all the 4430:{\displaystyle {\mathcal {P}}(\mathbb {N} )} 4335:, then there is no surjective function from 2435:This mapping covers all such ordered pairs. 1925: 1895: 1865: 1841: 1722: 1704: 1680: 1662: 1580: 1556: 1275: 1233: 1037: 1007: 987: 969: 7339: 7094: 6694:is empty or there is a surjective function 6068:{\displaystyle g_{i}:\mathbb {N} \to A_{i}} 4572:; and in both examples of non-well orders, 10134: 10120: 8561: 8376: 8362: 8338: 7663: 7649: 7395: 7315: 7291: 6833:{\displaystyle g\circ h:\mathbb {N} \to T} 6627:{\displaystyle h\circ f:S\to \mathbb {N} } 4518:, as well as many other kinds of numbers. 4495:but uncountable from the point of view of 2184:A subset of a countable set is countable. 8139: 8062: 8023: 7985: 7957: 7929: 7901: 7789: 7756: 7728: 7700: 7464:Fletcher, Peter; Patty, C. Wayne (1988), 7445: 7193: 7014: 6875:Finite intersection property#Applications 6820: 6708: 6620: 6548: 6390: 6341: 6295: 6212: 6048: 5696: 5688: 5476: 5454: 5446: 5363: 5355: 5347: 5319: 5170: 5162: 5134: 5044: 5036: 5002: 4994: 4954: 4920: 4791: 4783: 4775: 4747: 4739: 4661: 4638: 4420: 3190: 3168: 3003: 2981: 2956: 2893: 2611:-tuple to a natural number. For example, 2212: 2204: 1814: 1593:. For example, define the correspondence 1549: 1386: 1374: 1359: 1344: 1321: 1298: 779:{\displaystyle a_{0},a_{1},a_{2},\ldots } 690: 642: 516:All of these definitions are equivalent. 429: 360: 312: 263: 7416:"Ein Beitrag zur Mannigfaltigkeitslehre" 7042: 7040: 7038: 5114:on the number of sets in the collection. 4464:Minimal model of set theory is countable 3395: 2228: 1762:As for the case of infinite sets, a set 1100: 727:can be arranged in an infinite sequence 124: 7468:, Boston: PWS-KENT Publishing Company, 7370: 7236:FerreirĂłs 2007, pp. 268, 272–273. 6987: 6975: 6897: 5438:is a surjection from the countable set 5028:is a surjection from the countable set 4859:{\displaystyle f(m,n)=2^{m}\cdot 3^{n}} 4622: 4620: 137:to mean what is here called countable. 27:Mathematical set that can be enumerated 14: 10767: 8383: 7481: 7413: 7279: 7267: 7130: 6969: 6959: 6957: 6654:is countable. For (2) observe that if 4445:For an elaboration of this result see 2995:may intuitively seem much bigger than 2885:-tuples to the set of natural numbers 1281:{\displaystyle \{0,1,2,3,4,5,\dots \}} 90:In more technical terms, assuming the 10775:Basic concepts in infinite set theory 10115: 8357: 7644: 7554: 7541:, Berlin, New York: Springer-Verlag, 7512: 7303: 7142: 7073: 7067: 7047:Yaqub, Aladdin M. (24 October 2014). 7046: 7035: 6994:. BoD - Books on Demand. p. 24. 6948: 6924: 4040:of the natural numbers is countable. 7533: 7450:(2nd revised ed.), BirkhĂ€user, 7398:Foundations for Advanced Mathematics 6963: 6918: 6219:{\displaystyle I\times \mathbb {N} } 4719:, which takes 0 as a natural number. 4617: 4600:Hilbert's paradox of the Grand Hotel 1963:{\displaystyle n\leftrightarrow n+1} 1931:{\displaystyle B=\{0,2,4,6,\dots \}} 1782:is countably infinite if there is a 1043:{\displaystyle \{1,2,3,\dots ,100\}} 7852:Set-theoretically definable numbers 7575: 7560:Principles of Mathematical Analysis 7181: 7021:. Academic Publishers. p. 22. 6954: 6936: 6871:Cantor's first uncountability proof 6800:are both empty, or the composition 6721:{\displaystyle h:\mathbb {N} \to S} 6555:{\displaystyle h:T\to \mathbb {N} } 6262:{\textstyle \bigcup _{i\in I}A_{i}} 5333:are countable because the function 5148:are countable because the function 4967:{\displaystyle g:\mathbb {N} \to B} 4933:{\displaystyle f:\mathbb {N} \to A} 3986: 3976: 3966: 3913: 3873: 3833: 3793: 3753: 3713: 3673: 3633: 3593: 3553: 3513: 3433: 3423: 3413: 1992:{\displaystyle n\leftrightarrow 2n} 35:. For the statistical concept, see 24: 7823: 7670: 7074:Singh, Tej Bahadur (17 May 2019). 4411: 4388:. A proof is given in the article 4364: 4287: 3404:For example, given countable sets 1871:{\displaystyle A=\{1,2,3,\dots \}} 1485: 1456: 904: 588: 505:{\displaystyle |S|<\aleph _{0}} 493: 229: 25: 10796: 7466:Foundations of Higher Mathematics 4381:{\displaystyle {\mathcal {P}}(A)} 4315:, i.e. the set of all subsets of 4304:{\displaystyle {\mathcal {P}}(A)} 4021:of natural numbers is countable. 1828:. As examples, consider the sets 1444:correspondence with the integers 252:), the cardinality of the set of 10165: 10095: 8337: 7628: 7616: 7257:from the original on 2020-09-18. 7247:"What Are Sets and Roster Form?" 6988:Thierry, Vialar (4 April 2017). 6453: 6445: 6095: 6000:{\displaystyle I=\{1,\dots ,n\}} 3373:of countable sets is countable. 3208:In a similar manner, the set of 2438:This form of triangular mapping 2196:of two sets of natural numbers, 935:, Cantor proved that the set of 7400:, Scott, Foresman and Company, 7333: 7321: 7309: 7297: 7285: 7273: 7261: 7239: 7230: 7221: 7187: 7175: 7161:. World Scientific. p. 8. 7148: 7136: 7124: 7015:Mukherjee, Subir Kumar (2009). 6898:Manetti, Marco (19 June 2015). 6863: 6499: 6272: 6191:{\displaystyle G(i,m)=g_{i}(m)} 6027:there is a surjective function 5907: 5493: 5117: 4722: 4715:and the standard convention in 4521: 4514:and all effectively computable 1422:{\displaystyle n\rightarrow 2n} 1206:, infinite sets have more than 947: 10141: 7831:{\displaystyle {\mathcal {P}}} 7491:, D. Van Nostrand Company, Inc 7008: 6981: 6942: 6930: 6891: 6840:is surjective. In either case 6824: 6744: 6712: 6616: 6578: 6544: 6457: 6302:{\displaystyle I=\mathbb {N} } 6185: 6179: 6163: 6151: 6099: 6052: 5726: 5720: 5692: 5431:{\displaystyle g(m,n)=m/(n+1)} 5425: 5413: 5399: 5387: 5359: 5262: 5256: 5200: 5194: 5166: 5006: 4958: 4924: 4827: 4815: 4787: 4530:in various ways, for example: 4424: 4416: 4375: 4369: 4298: 4292: 4189: 4114: 3905: 3893: 3865: 3853: 3825: 3813: 3785: 3773: 3745: 3733: 3705: 3693: 3665: 3653: 3625: 3613: 3585: 3573: 3545: 3533: 3505: 3493: 3346: 3334: 3182:(the set of all integers) and 2852: 2840: 2820: 2808: 2788: 2776: 2756: 2747: 2735: 2732: 2712: 2700: 2680: 2671: 2659: 2656: 2636: 2618: 2531: 2473: 2416: 2404: 2401: 2392: 2380: 2377: 2368: 2356: 2353: 2344: 2332: 2329: 2320: 2308: 2305: 2296: 2284: 2281: 2272: 2260: 2257: 2146: 2132: 2118: 2104: 2090: 2069: 2055: 2041: 2027: 2013: 1980: 1948: 1633: 1618: 1603: 1448:and say they have cardinality 1410: 1379: 1364: 1349: 1330: 1307: 1050:presumably denotes the set of 566: 558: 485: 477: 207: 199: 113:, who proved the existence of 13: 1: 10056:History of mathematical logic 8186:Plane-based geometric algebra 7364: 7018:First Course in Real Analysis 6594:is injective the composition 6281:: As in the finite case, but 4437:is not countable; i.e. it is 4017:The set of all finite-length 155: 109:The concept is attributed to 48:(recursively) enumerable sets 9981:Primitive recursive function 8146:{\displaystyle \mathbb {S} } 8069:{\displaystyle \mathbb {C} } 8030:{\displaystyle \mathbb {R} } 7992:{\displaystyle \mathbb {O} } 7964:{\displaystyle \mathbb {H} } 7936:{\displaystyle \mathbb {C} } 7908:{\displaystyle \mathbb {R} } 7796:{\displaystyle \mathbb {A} } 7763:{\displaystyle \mathbb {Q} } 7735:{\displaystyle \mathbb {Z} } 7707:{\displaystyle \mathbb {N} } 7539:Real and Functional Analysis 7432:10.1515/crelle-1878-18788413 7050:An Introduction to Metalogic 6884: 6397:{\displaystyle \mathbb {N} } 6348:{\displaystyle \mathbb {N} } 5943:is a countable set for each 5483:{\displaystyle \mathbb {Q} } 5326:{\displaystyle \mathbb {Q} } 5141:{\displaystyle \mathbb {Z} } 4645:{\displaystyle \mathbb {N} } 4484:contains elements that are: 3197:{\displaystyle \mathbb {Q} } 3175:{\displaystyle \mathbb {Z} } 3010:{\displaystyle \mathbb {N} } 2988:{\displaystyle \mathbb {Q} } 2963:{\displaystyle \mathbb {Z} } 2900:{\displaystyle \mathbb {N} } 1821:{\displaystyle \mathbb {N} } 1113:; these sets have more than 933:his first set theory article 697:{\displaystyle \mathbb {N} } 649:{\displaystyle \mathbb {N} } 436:{\displaystyle \mathbb {N} } 367:{\displaystyle \mathbb {N} } 319:{\displaystyle \mathbb {N} } 270:{\displaystyle \mathbb {N} } 7: 7590:10.1007/978-981-10-1789-6_8 5284:{\displaystyle f(n)=3^{-n}} 4583: 3029:(a fraction in the form of 1686:{\displaystyle S=\{a,b,c\}} 1468:{\displaystyle \aleph _{0}} 1199:{\displaystyle n=10^{1000}} 916:{\displaystyle \aleph _{0}} 600:{\displaystyle \aleph _{0}} 348:is empty or there exists a 241:{\displaystyle \aleph _{0}} 10: 10801: 10625:von Neumann–Bernays–Gödel 9045:Schröder–Bernstein theorem 8772:Monadic predicate calculus 8431:Foundations of mathematics 7396:Avelsgaard, Carol (1990), 7346:. CRC Press. p. 141. 6978:, p. 23, Chapter 1.14 6508:: For (1) observe that if 5219:{\displaystyle f(n)=2^{n}} 5084:and the Corollary implies 4626:Since there is an obvious 4447:Cantor's diagonal argument 3275:is proved as countable if 2907:is proved. For the set of 2466:of natural numbers, i.e., 926: 29: 10689: 10652: 10564: 10454: 10426:One-to-one correspondence 10342: 10283: 10174: 10163: 10149: 10091: 10078:Philosophy of mathematics 10027:Automated theorem proving 10009: 9904: 9736: 9629: 9481: 9198: 9174: 9152:Von Neumann–Bernays–Gödel 9097: 8991: 8895: 8793: 8784: 8711: 8646: 8552: 8474: 8391: 8328: 8270: 8196: 8176:Algebra of physical space 8098: 8006: 7877: 7679: 7562:, New York: McGraw-Hill, 7328:Fletcher & Patty 1988 7227:Cantor 1878, p. 242. 7203:, CRC Press, p. 10, 7080:. Springer. p. 422. 6311:axiom of countable choice 5103:{\displaystyle A\times B} 5077:{\displaystyle A\times B} 3951:axiom of countable choice 3390:axiom of countable choice 2762:{\displaystyle ((0,2),3)} 2686:{\displaystyle ((0,2),3)} 1728:{\displaystyle \{1,2,3\}} 1431:one-to-one correspondence 993:{\displaystyle \{3,4,5\}} 680:one-to-one correspondence 221:is less than or equal to 92:axiom of countable choice 78:. Equivalently, a set is 72:one to one correspondence 8232:Extended complex numbers 8215:Extended natural numbers 7446:FerreirĂłs, JosĂ© (2007), 7077:Introduction to Topology 6904:. Springer. p. 26. 6877:for a topological proof. 6753:{\displaystyle g:S\to T} 6587:{\displaystyle f:S\to T} 6226:is countable, the union 6198:is a surjection. Since 4610: 4478:Löwenheim–Skolem theorem 4198:{\displaystyle g:S\to T} 4123:{\displaystyle f:S\to T} 2192:of natural numbers (the 512:) or countably infinite. 46:Not to be confused with 9728:Self-verifying theories 9549:Tarski's axiomatization 8500:Tarski's undefinability 8495:incompleteness theorems 6991:Handbook of Mathematics 6075:and hence the function 5647:{\displaystyle \alpha } 5515:{\displaystyle \alpha } 3096:{\displaystyle b\neq 0} 2642:{\displaystyle (0,2,3)} 2235:Cantor pairing function 1649:Since every element of 859:{\displaystyle i\neq j} 39:. For the company, see 10384:Constructible universe 10211:Constructibility (V=L) 10102:Mathematics portal 9713:Proof of impossibility 9361:propositional variable 8671:Propositional calculus 8288:Transcendental numbers 8147: 8124:Hyperbolic quaternions 8070: 8031: 7993: 7965: 7937: 7909: 7832: 7797: 7764: 7736: 7708: 7414:Cantor, Georg (1878), 6854: 6834: 6794: 6774: 6760:is surjective, either 6754: 6722: 6688: 6668: 6648: 6628: 6588: 6556: 6522: 6490: 6425: 6398: 6376: 6349: 6327: 6303: 6263: 6220: 6192: 6135: 6069: 6021: 6001: 5957: 5937: 5894: 5874: 5847: 5704: 5668: 5648: 5628: 5516: 5484: 5462: 5432: 5371: 5327: 5305: 5285: 5240: 5220: 5178: 5142: 5104: 5078: 5052: 5022: 4968: 4934: 4900: 4880: 4860: 4799: 4755: 4705: 4646: 4576:subsets do not have a 4526:Countable sets can be 4516:transcendental numbers 4474:Constructible universe 4431: 4382: 4349: 4329: 4305: 4272: 4239: 4219: 4199: 4164: 4144: 4124: 4088: 4068: 4036:The set of all finite 4001: 3941: 3448: 3401: 3353: 3321: 3289: 3269: 3249: 3229: 3198: 3176: 3145: 3117: 3097: 3071: 3051: 3011: 2989: 2964: 2921: 2901: 2879: 2859: 2827: 2795: 2763: 2719: 2687: 2643: 2605: 2585: 2565: 2538: 2456: 2429: 2238: 2220: 2168: 1993: 1964: 1932: 1878:, the set of positive 1872: 1822: 1800: 1776: 1753: 1729: 1687: 1643: 1587: 1532: 1504: 1469: 1423: 1394: 1282: 1220: 1200: 1167: 1147: 1127: 1106: 1092: 1072: 1044: 994: 917: 880: 860: 834: 807: 780: 721: 698: 672: 650: 628: 601: 574: 533: 506: 459: 437: 415: 388: 368: 342: 320: 298: 271: 242: 215: 174: 150:recursively enumerable 125:A note on terminology 10607:Principia Mathematica 10441:Transfinite induction 10300:(i.e. set difference) 9971:Kolmogorov complexity 9924:Computably enumerable 9824:Model complete theory 9616:Principia Mathematica 8676:Propositional formula 8505:Banach–Tarski paradox 8220:Extended real numbers 8148: 8071: 8041:Split-complex numbers 8032: 7994: 7966: 7938: 7910: 7833: 7798: 7774:Constructible numbers 7765: 7737: 7709: 7576:Tao, Terence (2016). 6855: 6835: 6795: 6775: 6755: 6723: 6689: 6674:is countable, either 6669: 6649: 6629: 6589: 6557: 6523: 6491: 6426: 6424:{\displaystyle A_{i}} 6399: 6377: 6375:{\displaystyle g_{i}} 6350: 6328: 6304: 6264: 6221: 6193: 6136: 6070: 6022: 6002: 5958: 5938: 5936:{\displaystyle A_{i}} 5895: 5875: 5873:{\displaystyle p_{n}} 5848: 5705: 5669: 5649: 5629: 5517: 5485: 5463: 5433: 5372: 5328: 5306: 5286: 5241: 5221: 5179: 5143: 5105: 5079: 5053: 5023: 4969: 4935: 4901: 4881: 4861: 4800: 4756: 4706: 4647: 4432: 4383: 4350: 4330: 4306: 4273: 4240: 4220: 4200: 4165: 4145: 4125: 4089: 4069: 4002: 3942: 3449: 3399: 3354: 3352:{\displaystyle (p,q)} 3322: 3290: 3270: 3250: 3230: 3199: 3177: 3146: 3118: 3098: 3072: 3052: 3012: 2990: 2965: 2922: 2902: 2880: 2860: 2858:{\displaystyle (a,b)} 2828: 2826:{\displaystyle (5,3)} 2796: 2794:{\displaystyle (5,3)} 2764: 2720: 2718:{\displaystyle (0,2)} 2688: 2644: 2606: 2586: 2566: 2564:{\displaystyle a_{i}} 2539: 2457: 2430: 2245:proceeds as follows: 2232: 2221: 2169: 1994: 1965: 1933: 1873: 1823: 1801: 1777: 1754: 1730: 1688: 1644: 1588: 1533: 1505: 1490:By definition, a set 1470: 1424: 1395: 1283: 1221: 1201: 1168: 1148: 1128: 1104: 1093: 1073: 1045: 995: 918: 881: 866:and every element of 861: 835: 833:{\displaystyle a_{j}} 808: 806:{\displaystyle a_{i}} 781: 722: 699: 673: 651: 629: 602: 575: 534: 507: 460: 438: 416: 389: 369: 343: 321: 299: 272: 243: 216: 175: 70:or it can be made in 10681:Burali-Forti paradox 10436:Set-builder notation 10389:Continuum hypothesis 10329:Symmetric difference 9919:Church–Turing thesis 9906:Computability theory 9115:continuum hypothesis 8633:Square of opposition 8491:Gödel's completeness 8252:Supernatural numbers 8162:Multicomplex numbers 8135: 8119:Dual-complex numbers 8058: 8019: 7981: 7953: 7925: 7897: 7879:Composition algebras 7847:Arithmetical numbers 7818: 7785: 7752: 7724: 7696: 7509:(Paperback edition). 6844: 6804: 6784: 6764: 6732: 6698: 6678: 6658: 6638: 6598: 6566: 6532: 6512: 6435: 6408: 6386: 6359: 6337: 6317: 6285: 6230: 6202: 6145: 6079: 6031: 6011: 5967: 5947: 5920: 5884: 5857: 5714: 5678: 5658: 5638: 5526: 5506: 5472: 5442: 5381: 5337: 5315: 5295: 5250: 5246:is non-negative and 5230: 5188: 5152: 5130: 5088: 5062: 5032: 4978: 4944: 4910: 4890: 4870: 4809: 4765: 4735: 4656: 4634: 4460:of natural numbers. 4406: 4359: 4339: 4319: 4282: 4262: 4229: 4209: 4177: 4154: 4134: 4102: 4078: 4058: 3961: 3458: 3408: 3331: 3303: 3279: 3259: 3239: 3219: 3186: 3164: 3127: 3107: 3081: 3061: 3033: 2999: 2977: 2952: 2911: 2889: 2869: 2837: 2805: 2773: 2729: 2697: 2653: 2615: 2595: 2575: 2548: 2470: 2446: 2251: 2200: 2003: 1974: 1942: 1886: 1832: 1810: 1790: 1766: 1743: 1701: 1653: 1597: 1545: 1538:and a subset of the 1522: 1494: 1452: 1404: 1400:or, more generally, 1292: 1230: 1210: 1177: 1157: 1137: 1117: 1082: 1062: 1004: 966: 900: 870: 844: 817: 790: 731: 711: 686: 662: 638: 618: 584: 554: 523: 473: 449: 425: 405: 378: 356: 332: 308: 288: 259: 225: 195: 164: 10642:Tarski–Grothendieck 10073:Mathematical object 9964:P versus NP problem 9929:Computable function 9723:Reverse mathematics 9649:Logical consequence 9526:primitive recursive 9521:elementary function 9294:Free/bound variable 9147:Tarski–Grothendieck 8666:Logical connectives 8596:Logical equivalence 8446:Logical consequence 8157:Split-biquaternions 7869:Eisenstein integers 7807:Closed-form numbers 7053:. Broadview Press. 4400: —  4052: —  4034: —  4015: —  3386: —  3367: —  3320:{\displaystyle p/q} 3159: —  3144:{\displaystyle n/1} 3123:is also a fraction 3050:{\displaystyle a/b} 2970:and the set of all 2935: —  2182: —  958:is a collection of 573:{\displaystyle |S|} 350:surjective function 214:{\displaystyle |S|} 82:if there exists an 10231:Limitation of size 9871:Transfer principle 9834:Semantics of logic 9819:Categorical theory 9795:Non-standard model 9309:Logical connective 8436:Information theory 8385:Mathematical logic 8315:Profinite integers 8278:Irrational numbers 8143: 8066: 8027: 7989: 7961: 7933: 7905: 7862:Gaussian rationals 7842:Computable numbers 7828: 7793: 7760: 7732: 7704: 7195:Stillwell, John C. 6850: 6830: 6790: 6770: 6750: 6718: 6684: 6664: 6644: 6624: 6584: 6552: 6518: 6486: 6475: 6421: 6394: 6372: 6345: 6323: 6299: 6259: 6248: 6216: 6188: 6131: 6117: 6065: 6017: 5997: 5953: 5933: 5890: 5870: 5843: 5700: 5664: 5644: 5624: 5512: 5480: 5458: 5428: 5367: 5323: 5301: 5281: 5236: 5216: 5174: 5138: 5100: 5074: 5048: 5018: 4964: 4930: 4896: 4876: 4856: 4795: 4751: 4717:mathematical logic 4701: 4642: 4492:, hence countable, 4427: 4398: 4378: 4345: 4325: 4301: 4268: 4235: 4225:is countable then 4215: 4205:is surjective and 4195: 4160: 4150:is countable then 4140: 4120: 4084: 4064: 4050: 4032: 4013: 3997: 3937: 3935: 3444: 3402: 3384: 3365: 3349: 3317: 3285: 3265: 3245: 3225: 3194: 3172: 3157: 3141: 3113: 3093: 3067: 3047: 3007: 2985: 2960: 2933: 2917: 2897: 2875: 2855: 2823: 2791: 2759: 2715: 2683: 2649:can be written as 2639: 2601: 2581: 2561: 2534: 2452: 2425: 2239: 2216: 2180: 2164: 2162: 1989: 1960: 1928: 1868: 1818: 1796: 1772: 1749: 1725: 1683: 1639: 1583: 1528: 1514:if there exists a 1500: 1465: 1446:countably infinite 1419: 1390: 1278: 1216: 1196: 1163: 1143: 1123: 1107: 1088: 1068: 1040: 990: 913: 876: 856: 830: 803: 776: 717: 694: 668: 646: 624: 614:) mapping between 597: 570: 529: 502: 455: 433: 411: 384: 364: 338: 316: 294: 282:injective function 267: 238: 211: 170: 104:countably infinite 84:injective function 18:Countably infinite 10762: 10761: 10671:Russell's paradox 10620:Zermelo–Fraenkel 10521:Dedekind-infinite 10394:Diagonal argument 10293:Cartesian product 10157:Set (mathematics) 10109: 10108: 10041:Abstract category 9844:Theories of truth 9654:Rule of inference 9644:Natural deduction 9625: 9624: 9170: 9169: 8875:Cartesian product 8780: 8779: 8686:Many-valued logic 8661:Boolean functions 8544:Russell's paradox 8519:diagonal argument 8416:First-order logic 8351: 8350: 8262:Superreal numbers 8242:Levi-Civita field 8237:Hyperreal numbers 8181:Spacetime algebra 8167:Geometric algebra 8080:Bicomplex numbers 8046:Split-quaternions 7887:Division algebras 7857:Gaussian integers 7779:Algebraic numbers 7682:definable numbers 7599:978-981-10-1789-6 7507:978-1-61427-131-4 7457:978-3-7643-8349-7 7389:978-0-471-00007-5 7353:978-0-8247-7915-3 7168:978-981-12-1999-3 7117:978-1-351-76532-9 7087:978-981-13-6954-4 7060:978-1-4604-0244-3 7028:978-81-89781-90-3 7001:978-2-9551990-1-5 6966:, §2 of Chapter I 6911:978-3-319-16958-3 6853:{\displaystyle T} 6793:{\displaystyle T} 6773:{\displaystyle S} 6687:{\displaystyle S} 6667:{\displaystyle S} 6647:{\displaystyle S} 6634:is injective, so 6521:{\displaystyle T} 6460: 6326:{\displaystyle i} 6313:to pick for each 6233: 6102: 6020:{\displaystyle i} 5956:{\displaystyle i} 5893:{\displaystyle n} 5667:{\displaystyle k} 5468:to the rationals 5304:{\displaystyle n} 5239:{\displaystyle n} 4899:{\displaystyle B} 4879:{\displaystyle A} 4512:algebraic numbers 4396: 4348:{\displaystyle A} 4328:{\displaystyle A} 4271:{\displaystyle A} 4238:{\displaystyle T} 4218:{\displaystyle S} 4163:{\displaystyle S} 4143:{\displaystyle T} 4130:is injective and 4087:{\displaystyle T} 4067:{\displaystyle S} 4048: 4030: 4011: 3988: 3978: 3968: 3915: 3875: 3835: 3795: 3755: 3715: 3675: 3635: 3595: 3555: 3515: 3482: 3475: 3468: 3435: 3425: 3415: 3382: 3363: 3288:{\displaystyle B} 3268:{\displaystyle A} 3248:{\displaystyle B} 3228:{\displaystyle A} 3210:algebraic numbers 3155: 3116:{\displaystyle n} 3070:{\displaystyle a} 2939:Cartesian product 2931: 2920:{\displaystyle n} 2878:{\displaystyle n} 2604:{\displaystyle n} 2584:{\displaystyle n} 2455:{\displaystyle n} 2194:Cartesian product 2178: 1799:{\displaystyle S} 1775:{\displaystyle S} 1752:{\displaystyle S} 1629: 1614: 1531:{\displaystyle S} 1503:{\displaystyle S} 1219:{\displaystyle n} 1166:{\displaystyle n} 1146:{\displaystyle n} 1126:{\displaystyle n} 1091:{\displaystyle n} 1071:{\displaystyle n} 879:{\displaystyle S} 813:is distinct from 720:{\displaystyle S} 671:{\displaystyle S} 627:{\displaystyle S} 532:{\displaystyle S} 458:{\displaystyle S} 414:{\displaystyle S} 387:{\displaystyle S} 341:{\displaystyle S} 297:{\displaystyle S} 173:{\displaystyle S} 135:at most countable 16:(Redirected from 10792: 10780:Cardinal numbers 10744:Bertrand Russell 10734:John von Neumann 10719:Abraham Fraenkel 10714:Richard Dedekind 10676:Suslin's problem 10587:Cantor's theorem 10304:De Morgan's laws 10169: 10136: 10129: 10122: 10113: 10112: 10100: 10099: 10051:History of logic 10046:Category of sets 9939:Decision problem 9718:Ordinal analysis 9659:Sequent calculus 9557:Boolean algebras 9497: 9496: 9471: 9442:logical/constant 9196: 9195: 9182: 9105:Zermelo–Fraenkel 8856:Set operations: 8791: 8790: 8728: 8559: 8558: 8539:Löwenheim–Skolem 8426:Formal semantics 8378: 8371: 8364: 8355: 8354: 8341: 8340: 8308: 8298: 8210:Cardinal numbers 8171:Clifford algebra 8152: 8150: 8149: 8144: 8142: 8114:Dual quaternions 8075: 8073: 8072: 8067: 8065: 8036: 8034: 8033: 8028: 8026: 7998: 7996: 7995: 7990: 7988: 7970: 7968: 7967: 7962: 7960: 7942: 7940: 7939: 7934: 7932: 7914: 7912: 7911: 7906: 7904: 7837: 7835: 7834: 7829: 7827: 7826: 7802: 7800: 7799: 7794: 7792: 7769: 7767: 7766: 7761: 7759: 7746:Rational numbers 7741: 7739: 7738: 7733: 7731: 7713: 7711: 7710: 7705: 7703: 7665: 7658: 7651: 7642: 7641: 7633: 7632: 7621: 7620: 7619: 7612: 7603: 7572: 7551: 7530: 7492: 7488:Naive Set Theory 7478: 7460: 7442: 7410: 7392: 7381: 7358: 7357: 7337: 7331: 7325: 7319: 7313: 7307: 7301: 7295: 7289: 7283: 7277: 7271: 7265: 7259: 7258: 7243: 7237: 7234: 7228: 7225: 7219: 7218: 7191: 7185: 7179: 7173: 7172: 7152: 7146: 7140: 7134: 7128: 7122: 7121: 7101: 7092: 7091: 7071: 7065: 7064: 7044: 7033: 7032: 7012: 7006: 7005: 6985: 6979: 6973: 6967: 6961: 6952: 6946: 6940: 6934: 6928: 6922: 6916: 6915: 6895: 6878: 6867: 6861: 6859: 6857: 6856: 6851: 6839: 6837: 6836: 6831: 6823: 6799: 6797: 6796: 6791: 6779: 6777: 6776: 6771: 6759: 6757: 6756: 6751: 6727: 6725: 6724: 6719: 6711: 6693: 6691: 6690: 6685: 6673: 6671: 6670: 6665: 6653: 6651: 6650: 6645: 6633: 6631: 6630: 6625: 6623: 6593: 6591: 6590: 6585: 6561: 6559: 6558: 6553: 6551: 6527: 6525: 6524: 6519: 6503: 6497: 6495: 6493: 6492: 6487: 6485: 6484: 6474: 6456: 6448: 6430: 6428: 6427: 6422: 6420: 6419: 6403: 6401: 6400: 6395: 6393: 6381: 6379: 6378: 6373: 6371: 6370: 6354: 6352: 6351: 6346: 6344: 6332: 6330: 6329: 6324: 6308: 6306: 6305: 6300: 6298: 6276: 6270: 6268: 6266: 6265: 6260: 6258: 6257: 6247: 6225: 6223: 6222: 6217: 6215: 6197: 6195: 6194: 6189: 6178: 6177: 6140: 6138: 6137: 6132: 6127: 6126: 6116: 6098: 6074: 6072: 6071: 6066: 6064: 6063: 6051: 6043: 6042: 6026: 6024: 6023: 6018: 6007:, then for each 6006: 6004: 6003: 5998: 5962: 5960: 5959: 5954: 5942: 5940: 5939: 5934: 5932: 5931: 5911: 5905: 5899: 5897: 5896: 5891: 5879: 5877: 5876: 5871: 5869: 5868: 5852: 5850: 5849: 5844: 5842: 5841: 5840: 5839: 5829: 5828: 5827: 5807: 5806: 5805: 5804: 5787: 5786: 5785: 5784: 5767: 5766: 5765: 5764: 5747: 5746: 5709: 5707: 5706: 5701: 5699: 5691: 5673: 5671: 5670: 5665: 5653: 5651: 5650: 5645: 5633: 5631: 5630: 5625: 5623: 5622: 5613: 5612: 5594: 5593: 5584: 5583: 5571: 5570: 5561: 5560: 5548: 5547: 5538: 5537: 5521: 5519: 5518: 5513: 5497: 5491: 5489: 5487: 5486: 5481: 5479: 5467: 5465: 5464: 5459: 5457: 5449: 5437: 5435: 5434: 5429: 5412: 5376: 5374: 5373: 5368: 5366: 5358: 5350: 5332: 5330: 5329: 5324: 5322: 5310: 5308: 5307: 5302: 5290: 5288: 5287: 5282: 5280: 5279: 5245: 5243: 5242: 5237: 5225: 5223: 5222: 5217: 5215: 5214: 5183: 5181: 5180: 5175: 5173: 5165: 5147: 5145: 5144: 5139: 5137: 5121: 5115: 5109: 5107: 5106: 5101: 5083: 5081: 5080: 5075: 5057: 5055: 5054: 5049: 5047: 5039: 5027: 5025: 5024: 5019: 5005: 4997: 4973: 4971: 4970: 4965: 4957: 4939: 4937: 4936: 4931: 4923: 4905: 4903: 4902: 4897: 4885: 4883: 4882: 4877: 4865: 4863: 4862: 4857: 4855: 4854: 4842: 4841: 4804: 4802: 4801: 4796: 4794: 4786: 4778: 4760: 4758: 4757: 4752: 4750: 4742: 4726: 4720: 4710: 4708: 4707: 4702: 4670: 4669: 4664: 4651: 4649: 4648: 4643: 4641: 4624: 4505:Skolem's paradox 4436: 4434: 4433: 4428: 4423: 4415: 4414: 4401: 4390:Cantor's theorem 4387: 4385: 4384: 4379: 4368: 4367: 4354: 4352: 4351: 4346: 4334: 4332: 4331: 4326: 4310: 4308: 4307: 4302: 4291: 4290: 4277: 4275: 4274: 4269: 4258:asserts that if 4255:Cantor's theorem 4244: 4242: 4241: 4236: 4224: 4222: 4221: 4216: 4204: 4202: 4201: 4196: 4173:If the function 4169: 4167: 4166: 4161: 4149: 4147: 4146: 4141: 4129: 4127: 4126: 4121: 4098:If the function 4093: 4091: 4090: 4085: 4073: 4071: 4070: 4065: 4053: 4035: 4016: 4007:simultaneously. 4006: 4004: 4003: 3998: 3990: 3989: 3980: 3979: 3970: 3969: 3946: 3944: 3943: 3938: 3936: 3933: 3932: 3923: 3922: 3917: 3916: 3883: 3882: 3877: 3876: 3843: 3842: 3837: 3836: 3803: 3802: 3797: 3796: 3763: 3762: 3757: 3756: 3723: 3722: 3717: 3716: 3683: 3682: 3677: 3676: 3643: 3642: 3637: 3636: 3603: 3602: 3597: 3596: 3563: 3562: 3557: 3556: 3523: 3522: 3517: 3516: 3483: 3480: 3476: 3473: 3469: 3466: 3453: 3451: 3450: 3445: 3437: 3436: 3427: 3426: 3417: 3416: 3387: 3368: 3358: 3356: 3355: 3350: 3326: 3324: 3323: 3318: 3313: 3297:rational numbers 3294: 3292: 3291: 3286: 3274: 3272: 3271: 3266: 3254: 3252: 3251: 3246: 3234: 3232: 3231: 3226: 3203: 3201: 3200: 3195: 3193: 3181: 3179: 3178: 3173: 3171: 3160: 3150: 3148: 3147: 3142: 3137: 3122: 3120: 3119: 3114: 3102: 3100: 3099: 3094: 3076: 3074: 3073: 3068: 3056: 3054: 3053: 3048: 3043: 3016: 3014: 3013: 3008: 3006: 2994: 2992: 2991: 2986: 2984: 2972:rational numbers 2969: 2967: 2966: 2961: 2959: 2936: 2926: 2924: 2923: 2918: 2906: 2904: 2903: 2898: 2896: 2884: 2882: 2881: 2876: 2864: 2862: 2861: 2856: 2832: 2830: 2829: 2824: 2800: 2798: 2797: 2792: 2768: 2766: 2765: 2760: 2724: 2722: 2721: 2716: 2692: 2690: 2689: 2684: 2648: 2646: 2645: 2640: 2610: 2608: 2607: 2602: 2590: 2588: 2587: 2582: 2570: 2568: 2567: 2562: 2560: 2559: 2543: 2541: 2540: 2535: 2530: 2529: 2511: 2510: 2498: 2497: 2485: 2484: 2461: 2459: 2458: 2453: 2434: 2432: 2431: 2426: 2225: 2223: 2222: 2217: 2215: 2207: 2183: 2173: 2171: 2170: 2165: 2163: 1998: 1996: 1995: 1990: 1969: 1967: 1966: 1961: 1937: 1935: 1934: 1929: 1877: 1875: 1874: 1869: 1827: 1825: 1824: 1819: 1817: 1805: 1803: 1802: 1797: 1781: 1779: 1778: 1773: 1758: 1756: 1755: 1750: 1734: 1732: 1731: 1726: 1692: 1690: 1689: 1684: 1648: 1646: 1645: 1640: 1627: 1612: 1592: 1590: 1589: 1584: 1552: 1537: 1535: 1534: 1529: 1509: 1507: 1506: 1501: 1474: 1472: 1471: 1466: 1464: 1463: 1428: 1426: 1425: 1420: 1399: 1397: 1396: 1391: 1287: 1285: 1284: 1279: 1225: 1223: 1222: 1217: 1205: 1203: 1202: 1197: 1195: 1194: 1172: 1170: 1169: 1164: 1152: 1150: 1149: 1144: 1132: 1130: 1129: 1124: 1097: 1095: 1094: 1089: 1077: 1075: 1074: 1069: 1049: 1047: 1046: 1041: 999: 997: 996: 991: 922: 920: 919: 914: 912: 911: 885: 883: 882: 877: 865: 863: 862: 857: 839: 837: 836: 831: 829: 828: 812: 810: 809: 804: 802: 801: 785: 783: 782: 777: 769: 768: 756: 755: 743: 742: 726: 724: 723: 718: 707:The elements of 703: 701: 700: 695: 693: 677: 675: 674: 669: 655: 653: 652: 647: 645: 633: 631: 630: 625: 606: 604: 603: 598: 596: 595: 579: 577: 576: 571: 569: 561: 550:Its cardinality 538: 536: 535: 530: 511: 509: 508: 503: 501: 500: 488: 480: 464: 462: 461: 456: 442: 440: 439: 434: 432: 421:and a subset of 420: 418: 417: 412: 401:mapping between 393: 391: 390: 385: 373: 371: 370: 365: 363: 347: 345: 344: 339: 325: 323: 322: 317: 315: 303: 301: 300: 295: 280:There exists an 276: 274: 273: 268: 266: 247: 245: 244: 239: 237: 236: 220: 218: 217: 212: 210: 202: 179: 177: 176: 171: 115:uncountable sets 74:with the set of 66:if either it is 51: 44: 21: 10800: 10799: 10795: 10794: 10793: 10791: 10790: 10789: 10765: 10764: 10763: 10758: 10685: 10664: 10648: 10613:New Foundations 10560: 10450: 10369:Cardinal number 10352: 10338: 10279: 10170: 10161: 10145: 10140: 10110: 10105: 10094: 10087: 10032:Category theory 10022:Algebraic logic 10005: 9976:Lambda calculus 9914:Church encoding 9900: 9876:Truth predicate 9732: 9698:Complete theory 9621: 9490: 9486: 9482: 9477: 9469: 9189: and  9185: 9180: 9166: 9142:New Foundations 9110:axiom of choice 9093: 9055:Gödel numbering 8995: and  8987: 8891: 8776: 8726: 8707: 8656:Boolean algebra 8642: 8606:Equiconsistency 8571:Classical logic 8548: 8529:Halting problem 8517: and  8493: and  8481: and  8480: 8475:Theorems ( 8470: 8387: 8382: 8352: 8347: 8324: 8303: 8293: 8266: 8257:Surreal numbers 8247:Ordinal numbers 8192: 8138: 8136: 8133: 8132: 8094: 8061: 8059: 8056: 8055: 8053: 8051:Split-octonions 8022: 8020: 8017: 8016: 8008: 8002: 7984: 7982: 7979: 7978: 7956: 7954: 7951: 7950: 7928: 7926: 7923: 7922: 7919:Complex numbers 7900: 7898: 7895: 7894: 7873: 7822: 7821: 7819: 7816: 7815: 7788: 7786: 7783: 7782: 7755: 7753: 7750: 7749: 7727: 7725: 7722: 7721: 7699: 7697: 7694: 7693: 7690:Natural numbers 7675: 7669: 7639: 7627: 7617: 7615: 7607: 7600: 7578:"Infinite sets" 7570: 7549: 7528: 7483:Halmos, Paul R. 7476: 7458: 7426:(84): 242–248, 7408: 7390: 7372:Apostol, Tom M. 7367: 7362: 7361: 7354: 7338: 7334: 7326: 7322: 7316:Avelsgaard 1990 7314: 7310: 7302: 7298: 7292:Avelsgaard 1990 7290: 7286: 7278: 7274: 7266: 7262: 7245: 7244: 7240: 7235: 7231: 7226: 7222: 7211: 7192: 7188: 7180: 7176: 7169: 7153: 7149: 7141: 7137: 7129: 7125: 7118: 7102: 7095: 7088: 7072: 7068: 7061: 7045: 7036: 7029: 7013: 7009: 7002: 6986: 6982: 6974: 6970: 6962: 6955: 6947: 6943: 6935: 6931: 6923: 6919: 6912: 6896: 6892: 6887: 6882: 6881: 6868: 6864: 6845: 6842: 6841: 6819: 6805: 6802: 6801: 6785: 6782: 6781: 6765: 6762: 6761: 6733: 6730: 6729: 6707: 6699: 6696: 6695: 6679: 6676: 6675: 6659: 6656: 6655: 6639: 6636: 6635: 6619: 6599: 6596: 6595: 6567: 6564: 6563: 6547: 6533: 6530: 6529: 6513: 6510: 6509: 6504: 6500: 6480: 6476: 6464: 6452: 6444: 6436: 6433: 6432: 6415: 6411: 6409: 6406: 6405: 6389: 6387: 6384: 6383: 6366: 6362: 6360: 6357: 6356: 6340: 6338: 6335: 6334: 6318: 6315: 6314: 6309:and we use the 6294: 6286: 6283: 6282: 6277: 6273: 6253: 6249: 6237: 6231: 6228: 6227: 6211: 6203: 6200: 6199: 6173: 6169: 6146: 6143: 6142: 6122: 6118: 6106: 6094: 6080: 6077: 6076: 6059: 6055: 6047: 6038: 6034: 6032: 6029: 6028: 6012: 6009: 6008: 5968: 5965: 5964: 5948: 5945: 5944: 5927: 5923: 5921: 5918: 5917: 5912: 5908: 5885: 5882: 5881: 5864: 5860: 5858: 5855: 5854: 5835: 5831: 5830: 5817: 5813: 5812: 5811: 5800: 5796: 5795: 5791: 5780: 5776: 5775: 5771: 5760: 5756: 5755: 5751: 5736: 5732: 5715: 5712: 5711: 5695: 5687: 5679: 5676: 5675: 5659: 5656: 5655: 5639: 5636: 5635: 5618: 5614: 5608: 5604: 5589: 5585: 5579: 5575: 5566: 5562: 5556: 5552: 5543: 5539: 5533: 5529: 5527: 5524: 5523: 5507: 5504: 5503: 5498: 5494: 5475: 5473: 5470: 5469: 5453: 5445: 5443: 5440: 5439: 5408: 5382: 5379: 5378: 5362: 5354: 5346: 5338: 5335: 5334: 5318: 5316: 5313: 5312: 5296: 5293: 5292: 5272: 5268: 5251: 5248: 5247: 5231: 5228: 5227: 5210: 5206: 5189: 5186: 5185: 5169: 5161: 5153: 5150: 5149: 5133: 5131: 5128: 5127: 5122: 5118: 5089: 5086: 5085: 5063: 5060: 5059: 5043: 5035: 5033: 5030: 5029: 5001: 4993: 4979: 4976: 4975: 4953: 4945: 4942: 4941: 4919: 4911: 4908: 4907: 4891: 4888: 4887: 4871: 4868: 4867: 4850: 4846: 4837: 4833: 4810: 4807: 4806: 4790: 4782: 4774: 4766: 4763: 4762: 4746: 4738: 4736: 4733: 4732: 4727: 4723: 4665: 4660: 4659: 4657: 4654: 4653: 4637: 4635: 4632: 4631: 4625: 4618: 4613: 4605:Uncountable set 4586: 4528:totally ordered 4524: 4466: 4443: 4419: 4410: 4409: 4407: 4404: 4403: 4399: 4363: 4362: 4360: 4357: 4356: 4340: 4337: 4336: 4320: 4317: 4316: 4286: 4285: 4283: 4280: 4279: 4263: 4260: 4259: 4248: 4230: 4227: 4226: 4210: 4207: 4206: 4178: 4175: 4174: 4155: 4152: 4151: 4135: 4132: 4131: 4103: 4100: 4099: 4079: 4076: 4075: 4059: 4056: 4055: 4051: 4042: 4033: 4023: 4014: 3985: 3984: 3975: 3974: 3965: 3964: 3962: 3959: 3958: 3934: 3931: 3925: 3924: 3918: 3912: 3911: 3910: 3908: 3891: 3885: 3884: 3878: 3872: 3871: 3870: 3868: 3851: 3845: 3844: 3838: 3832: 3831: 3830: 3828: 3811: 3805: 3804: 3798: 3792: 3791: 3790: 3788: 3771: 3765: 3764: 3758: 3752: 3751: 3750: 3748: 3731: 3725: 3724: 3718: 3712: 3711: 3710: 3708: 3691: 3685: 3684: 3678: 3672: 3671: 3670: 3668: 3651: 3645: 3644: 3638: 3632: 3631: 3630: 3628: 3611: 3605: 3604: 3598: 3592: 3591: 3590: 3588: 3571: 3565: 3564: 3558: 3552: 3551: 3550: 3548: 3531: 3525: 3524: 3518: 3512: 3511: 3510: 3508: 3491: 3485: 3484: 3479: 3477: 3472: 3470: 3465: 3461: 3459: 3456: 3455: 3432: 3431: 3422: 3421: 3412: 3411: 3409: 3406: 3405: 3394: 3385: 3375: 3366: 3332: 3329: 3328: 3309: 3304: 3301: 3300: 3280: 3277: 3276: 3260: 3257: 3256: 3240: 3237: 3236: 3220: 3217: 3216: 3206: 3189: 3187: 3184: 3183: 3167: 3165: 3162: 3161: 3158: 3133: 3128: 3125: 3124: 3108: 3105: 3104: 3082: 3079: 3078: 3062: 3059: 3058: 3039: 3034: 3031: 3030: 3027:vulgar fraction 3002: 3000: 2997: 2996: 2980: 2978: 2975: 2974: 2955: 2953: 2950: 2949: 2945:The set of all 2943: 2934: 2912: 2909: 2908: 2892: 2890: 2887: 2886: 2870: 2867: 2866: 2838: 2835: 2834: 2806: 2803: 2802: 2774: 2771: 2770: 2730: 2727: 2726: 2698: 2695: 2694: 2654: 2651: 2650: 2616: 2613: 2612: 2596: 2593: 2592: 2576: 2573: 2572: 2555: 2551: 2549: 2546: 2545: 2525: 2521: 2506: 2502: 2493: 2489: 2480: 2476: 2471: 2468: 2467: 2447: 2444: 2443: 2442:generalizes to 2252: 2249: 2248: 2211: 2203: 2201: 2198: 2197: 2188:The set of all 2186: 2181: 2161: 2160: 2155: 2141: 2127: 2113: 2099: 2084: 2083: 2078: 2064: 2050: 2036: 2022: 2006: 2004: 2001: 2000: 1975: 1972: 1971: 1943: 1940: 1939: 1887: 1884: 1883: 1833: 1830: 1829: 1813: 1811: 1808: 1807: 1791: 1788: 1787: 1767: 1764: 1763: 1744: 1741: 1740: 1702: 1699: 1698: 1693:is paired with 1654: 1651: 1650: 1598: 1595: 1594: 1548: 1546: 1543: 1542: 1540:natural numbers 1523: 1520: 1519: 1495: 1492: 1491: 1488: 1486:Formal overview 1459: 1455: 1453: 1450: 1449: 1405: 1402: 1401: 1293: 1290: 1289: 1231: 1228: 1227: 1211: 1208: 1207: 1190: 1186: 1178: 1175: 1174: 1158: 1155: 1154: 1138: 1135: 1134: 1133:elements where 1118: 1115: 1114: 1083: 1080: 1079: 1063: 1060: 1059: 1005: 1002: 1001: 967: 964: 963: 950: 929: 907: 903: 901: 898: 897: 871: 868: 867: 845: 842: 841: 824: 820: 818: 815: 814: 797: 793: 791: 788: 787: 764: 760: 751: 747: 738: 734: 732: 729: 728: 712: 709: 708: 689: 687: 684: 683: 663: 660: 659: 641: 639: 636: 635: 619: 616: 615: 591: 587: 585: 582: 581: 565: 557: 555: 552: 551: 524: 521: 520: 496: 492: 484: 476: 474: 471: 470: 450: 447: 446: 428: 426: 423: 422: 406: 403: 402: 397:There exists a 379: 376: 375: 359: 357: 354: 353: 333: 330: 329: 311: 309: 306: 305: 289: 286: 285: 262: 260: 257: 256: 254:natural numbers 232: 228: 226: 223: 222: 206: 198: 196: 193: 192: 165: 162: 161: 158: 127: 76:natural numbers 52: 45: 41:Countable (app) 30: 28: 23: 22: 15: 12: 11: 5: 10798: 10788: 10787: 10782: 10777: 10760: 10759: 10757: 10756: 10751: 10749:Thoralf Skolem 10746: 10741: 10736: 10731: 10726: 10721: 10716: 10711: 10706: 10701: 10695: 10693: 10687: 10686: 10684: 10683: 10678: 10673: 10667: 10665: 10663: 10662: 10659: 10653: 10650: 10649: 10647: 10646: 10645: 10644: 10639: 10634: 10633: 10632: 10617: 10616: 10615: 10603: 10602: 10601: 10590: 10589: 10584: 10579: 10574: 10568: 10566: 10562: 10561: 10559: 10558: 10553: 10548: 10543: 10534: 10529: 10524: 10514: 10509: 10508: 10507: 10502: 10497: 10487: 10477: 10472: 10467: 10461: 10459: 10452: 10451: 10449: 10448: 10443: 10438: 10433: 10431:Ordinal number 10428: 10423: 10418: 10413: 10412: 10411: 10406: 10396: 10391: 10386: 10381: 10376: 10366: 10361: 10355: 10353: 10351: 10350: 10347: 10343: 10340: 10339: 10337: 10336: 10331: 10326: 10321: 10316: 10311: 10309:Disjoint union 10306: 10301: 10295: 10289: 10287: 10281: 10280: 10278: 10277: 10276: 10275: 10270: 10259: 10258: 10256:Martin's axiom 10253: 10248: 10243: 10238: 10233: 10228: 10223: 10221:Extensionality 10218: 10213: 10208: 10207: 10206: 10201: 10196: 10186: 10180: 10178: 10172: 10171: 10164: 10162: 10160: 10159: 10153: 10151: 10147: 10146: 10139: 10138: 10131: 10124: 10116: 10107: 10106: 10092: 10089: 10088: 10086: 10085: 10080: 10075: 10070: 10065: 10064: 10063: 10053: 10048: 10043: 10034: 10029: 10024: 10019: 10017:Abstract logic 10013: 10011: 10007: 10006: 10004: 10003: 9998: 9996:Turing machine 9993: 9988: 9983: 9978: 9973: 9968: 9967: 9966: 9961: 9956: 9951: 9946: 9936: 9934:Computable set 9931: 9926: 9921: 9916: 9910: 9908: 9902: 9901: 9899: 9898: 9893: 9888: 9883: 9878: 9873: 9868: 9863: 9862: 9861: 9856: 9851: 9841: 9836: 9831: 9829:Satisfiability 9826: 9821: 9816: 9815: 9814: 9804: 9803: 9802: 9792: 9791: 9790: 9785: 9780: 9775: 9770: 9760: 9759: 9758: 9753: 9746:Interpretation 9742: 9740: 9734: 9733: 9731: 9730: 9725: 9720: 9715: 9710: 9700: 9695: 9694: 9693: 9692: 9691: 9681: 9676: 9666: 9661: 9656: 9651: 9646: 9641: 9635: 9633: 9627: 9626: 9623: 9622: 9620: 9619: 9611: 9610: 9609: 9608: 9603: 9602: 9601: 9596: 9591: 9571: 9570: 9569: 9567:minimal axioms 9564: 9553: 9552: 9551: 9540: 9539: 9538: 9533: 9528: 9523: 9518: 9513: 9500: 9498: 9479: 9478: 9476: 9475: 9474: 9473: 9461: 9456: 9455: 9454: 9449: 9444: 9439: 9429: 9424: 9419: 9414: 9413: 9412: 9407: 9397: 9396: 9395: 9390: 9385: 9380: 9370: 9365: 9364: 9363: 9358: 9353: 9343: 9342: 9341: 9336: 9331: 9326: 9321: 9316: 9306: 9301: 9296: 9291: 9290: 9289: 9284: 9279: 9274: 9264: 9259: 9257:Formation rule 9254: 9249: 9248: 9247: 9242: 9232: 9231: 9230: 9220: 9215: 9210: 9205: 9199: 9193: 9176:Formal systems 9172: 9171: 9168: 9167: 9165: 9164: 9159: 9154: 9149: 9144: 9139: 9134: 9129: 9124: 9119: 9118: 9117: 9112: 9101: 9099: 9095: 9094: 9092: 9091: 9090: 9089: 9079: 9074: 9073: 9072: 9065:Large cardinal 9062: 9057: 9052: 9047: 9042: 9028: 9027: 9026: 9021: 9016: 9001: 8999: 8989: 8988: 8986: 8985: 8984: 8983: 8978: 8973: 8963: 8958: 8953: 8948: 8943: 8938: 8933: 8928: 8923: 8918: 8913: 8908: 8902: 8900: 8893: 8892: 8890: 8889: 8888: 8887: 8882: 8877: 8872: 8867: 8862: 8854: 8853: 8852: 8847: 8837: 8832: 8830:Extensionality 8827: 8825:Ordinal number 8822: 8812: 8807: 8806: 8805: 8794: 8788: 8782: 8781: 8778: 8777: 8775: 8774: 8769: 8764: 8759: 8754: 8749: 8744: 8743: 8742: 8732: 8731: 8730: 8717: 8715: 8709: 8708: 8706: 8705: 8704: 8703: 8698: 8693: 8683: 8678: 8673: 8668: 8663: 8658: 8652: 8650: 8644: 8643: 8641: 8640: 8635: 8630: 8625: 8620: 8615: 8610: 8609: 8608: 8598: 8593: 8588: 8583: 8578: 8573: 8567: 8565: 8556: 8550: 8549: 8547: 8546: 8541: 8536: 8531: 8526: 8521: 8509:Cantor's  8507: 8502: 8497: 8487: 8485: 8472: 8471: 8469: 8468: 8463: 8458: 8453: 8448: 8443: 8438: 8433: 8428: 8423: 8418: 8413: 8408: 8407: 8406: 8395: 8393: 8389: 8388: 8381: 8380: 8373: 8366: 8358: 8349: 8348: 8346: 8345: 8335: 8333:Classification 8329: 8326: 8325: 8323: 8322: 8320:Normal numbers 8317: 8312: 8290: 8285: 8280: 8274: 8272: 8268: 8267: 8265: 8264: 8259: 8254: 8249: 8244: 8239: 8234: 8229: 8228: 8227: 8217: 8212: 8206: 8204: 8202:infinitesimals 8194: 8193: 8191: 8190: 8189: 8188: 8183: 8178: 8164: 8159: 8154: 8141: 8126: 8121: 8116: 8111: 8105: 8103: 8096: 8095: 8093: 8092: 8087: 8082: 8077: 8064: 8048: 8043: 8038: 8025: 8012: 8010: 8004: 8003: 8001: 8000: 7987: 7972: 7959: 7944: 7931: 7916: 7903: 7883: 7881: 7875: 7874: 7872: 7871: 7866: 7865: 7864: 7854: 7849: 7844: 7839: 7825: 7809: 7804: 7791: 7776: 7771: 7758: 7743: 7730: 7715: 7702: 7686: 7684: 7677: 7676: 7668: 7667: 7660: 7653: 7645: 7638: 7637: 7625: 7605: 7604: 7598: 7573: 7568: 7552: 7547: 7531: 7527:978-0486601410 7526: 7518:Theory of Sets 7510: 7479: 7474: 7461: 7456: 7443: 7411: 7406: 7393: 7388: 7366: 7363: 7360: 7359: 7352: 7332: 7320: 7308: 7306:, pp. 3–4 7296: 7284: 7272: 7260: 7253:. 2021-05-09. 7238: 7229: 7220: 7216:been imagined. 7209: 7186: 7174: 7167: 7147: 7135: 7123: 7116: 7093: 7086: 7066: 7059: 7034: 7027: 7007: 7000: 6980: 6968: 6953: 6941: 6929: 6917: 6910: 6889: 6888: 6886: 6883: 6880: 6879: 6862: 6849: 6829: 6826: 6822: 6818: 6815: 6812: 6809: 6789: 6769: 6749: 6746: 6743: 6740: 6737: 6717: 6714: 6710: 6706: 6703: 6683: 6663: 6643: 6622: 6618: 6615: 6612: 6609: 6606: 6603: 6583: 6580: 6577: 6574: 6571: 6550: 6546: 6543: 6540: 6537: 6517: 6498: 6483: 6479: 6473: 6470: 6467: 6463: 6459: 6455: 6451: 6447: 6443: 6440: 6418: 6414: 6392: 6369: 6365: 6343: 6322: 6297: 6293: 6290: 6271: 6256: 6252: 6246: 6243: 6240: 6236: 6214: 6210: 6207: 6187: 6184: 6181: 6176: 6172: 6168: 6165: 6162: 6159: 6156: 6153: 6150: 6130: 6125: 6121: 6115: 6112: 6109: 6105: 6101: 6097: 6093: 6090: 6087: 6084: 6062: 6058: 6054: 6050: 6046: 6041: 6037: 6016: 5996: 5993: 5990: 5987: 5984: 5981: 5978: 5975: 5972: 5952: 5930: 5926: 5906: 5889: 5867: 5863: 5838: 5834: 5826: 5823: 5820: 5816: 5810: 5803: 5799: 5794: 5790: 5783: 5779: 5774: 5770: 5763: 5759: 5754: 5750: 5745: 5742: 5739: 5735: 5731: 5728: 5725: 5722: 5719: 5698: 5694: 5690: 5686: 5683: 5663: 5643: 5621: 5617: 5611: 5607: 5603: 5600: 5597: 5592: 5588: 5582: 5578: 5574: 5569: 5565: 5559: 5555: 5551: 5546: 5542: 5536: 5532: 5511: 5492: 5478: 5456: 5452: 5448: 5427: 5424: 5421: 5418: 5415: 5411: 5407: 5404: 5401: 5398: 5395: 5392: 5389: 5386: 5365: 5361: 5357: 5353: 5349: 5345: 5342: 5321: 5300: 5278: 5275: 5271: 5267: 5264: 5261: 5258: 5255: 5235: 5213: 5209: 5205: 5202: 5199: 5196: 5193: 5172: 5168: 5164: 5160: 5157: 5136: 5116: 5099: 5096: 5093: 5073: 5070: 5067: 5046: 5042: 5038: 5017: 5014: 5011: 5008: 5004: 5000: 4996: 4992: 4989: 4986: 4983: 4963: 4960: 4956: 4952: 4949: 4929: 4926: 4922: 4918: 4915: 4895: 4875: 4853: 4849: 4845: 4840: 4836: 4832: 4829: 4826: 4823: 4820: 4817: 4814: 4793: 4789: 4785: 4781: 4777: 4773: 4770: 4749: 4745: 4741: 4721: 4700: 4697: 4694: 4691: 4688: 4685: 4682: 4679: 4676: 4673: 4668: 4663: 4640: 4615: 4614: 4612: 4609: 4608: 4607: 4602: 4597: 4592: 4585: 4582: 4566: 4565: 4564: 4563: 4560: 4556:well orders): 4550: 4549: 4548: 4545: 4539:ordinal number 4523: 4520: 4501: 4500: 4493: 4465: 4462: 4426: 4422: 4418: 4413: 4394: 4377: 4374: 4371: 4366: 4344: 4324: 4300: 4297: 4294: 4289: 4267: 4247: 4246: 4234: 4214: 4194: 4191: 4188: 4185: 4182: 4171: 4159: 4139: 4119: 4116: 4113: 4110: 4107: 4083: 4063: 4046: 4028: 4009: 3996: 3993: 3983: 3973: 3930: 3927: 3926: 3921: 3909: 3907: 3904: 3901: 3898: 3895: 3892: 3890: 3887: 3886: 3881: 3869: 3867: 3864: 3861: 3858: 3855: 3852: 3850: 3847: 3846: 3841: 3829: 3827: 3824: 3821: 3818: 3815: 3812: 3810: 3807: 3806: 3801: 3789: 3787: 3784: 3781: 3778: 3775: 3772: 3770: 3767: 3766: 3761: 3749: 3747: 3744: 3741: 3738: 3735: 3732: 3730: 3727: 3726: 3721: 3709: 3707: 3704: 3701: 3698: 3695: 3692: 3690: 3687: 3686: 3681: 3669: 3667: 3664: 3661: 3658: 3655: 3652: 3650: 3647: 3646: 3641: 3629: 3627: 3624: 3621: 3618: 3615: 3612: 3610: 3607: 3606: 3601: 3589: 3587: 3584: 3581: 3578: 3575: 3572: 3570: 3567: 3566: 3561: 3549: 3547: 3544: 3541: 3538: 3535: 3532: 3530: 3527: 3526: 3521: 3509: 3507: 3504: 3501: 3498: 3495: 3492: 3490: 3487: 3486: 3478: 3471: 3464: 3463: 3443: 3440: 3430: 3420: 3388:(Assuming the 3380: 3361: 3348: 3345: 3342: 3339: 3336: 3316: 3312: 3308: 3284: 3264: 3244: 3224: 3212:is countable. 3192: 3170: 3153: 3140: 3136: 3132: 3112: 3092: 3089: 3086: 3066: 3046: 3042: 3038: 3005: 2983: 2958: 2929: 2916: 2895: 2874: 2854: 2851: 2848: 2845: 2842: 2822: 2819: 2816: 2813: 2810: 2790: 2787: 2784: 2781: 2778: 2758: 2755: 2752: 2749: 2746: 2743: 2740: 2737: 2734: 2714: 2711: 2708: 2705: 2702: 2682: 2679: 2676: 2673: 2670: 2667: 2664: 2661: 2658: 2638: 2635: 2632: 2629: 2626: 2623: 2620: 2600: 2580: 2558: 2554: 2533: 2528: 2524: 2520: 2517: 2514: 2509: 2505: 2501: 2496: 2492: 2488: 2483: 2479: 2475: 2451: 2424: 2421: 2418: 2415: 2412: 2409: 2406: 2403: 2400: 2397: 2394: 2391: 2388: 2385: 2382: 2379: 2376: 2373: 2370: 2367: 2364: 2361: 2358: 2355: 2352: 2349: 2346: 2343: 2340: 2337: 2334: 2331: 2328: 2325: 2322: 2319: 2316: 2313: 2310: 2307: 2304: 2301: 2298: 2295: 2292: 2289: 2286: 2283: 2280: 2277: 2274: 2271: 2268: 2265: 2262: 2259: 2256: 2241:The resulting 2214: 2210: 2206: 2176: 2159: 2156: 2154: 2151: 2148: 2145: 2142: 2140: 2137: 2134: 2131: 2128: 2126: 2123: 2120: 2117: 2114: 2112: 2109: 2106: 2103: 2100: 2098: 2095: 2092: 2089: 2086: 2085: 2082: 2079: 2077: 2074: 2071: 2068: 2065: 2063: 2060: 2057: 2054: 2051: 2049: 2046: 2043: 2040: 2037: 2035: 2032: 2029: 2026: 2023: 2021: 2018: 2015: 2012: 2009: 2008: 1988: 1985: 1982: 1979: 1959: 1956: 1953: 1950: 1947: 1927: 1924: 1921: 1918: 1915: 1912: 1909: 1906: 1903: 1900: 1897: 1894: 1891: 1867: 1864: 1861: 1858: 1855: 1852: 1849: 1846: 1843: 1840: 1837: 1816: 1795: 1771: 1748: 1724: 1721: 1718: 1715: 1712: 1709: 1706: 1682: 1679: 1676: 1673: 1670: 1667: 1664: 1661: 1658: 1638: 1635: 1632: 1626: 1623: 1620: 1617: 1611: 1608: 1605: 1602: 1582: 1579: 1576: 1573: 1570: 1567: 1564: 1561: 1558: 1555: 1551: 1527: 1499: 1487: 1484: 1462: 1458: 1439:), which is a 1418: 1415: 1412: 1409: 1389: 1385: 1381: 1377: 1373: 1370: 1366: 1362: 1358: 1355: 1351: 1347: 1343: 1340: 1336: 1332: 1328: 1324: 1320: 1317: 1313: 1309: 1305: 1301: 1297: 1277: 1274: 1271: 1268: 1265: 1262: 1259: 1256: 1253: 1250: 1247: 1244: 1241: 1238: 1235: 1215: 1193: 1189: 1185: 1182: 1162: 1142: 1122: 1109:Some sets are 1087: 1067: 1039: 1036: 1033: 1030: 1027: 1024: 1021: 1018: 1015: 1012: 1009: 989: 986: 983: 980: 977: 974: 971: 949: 946: 928: 925: 910: 906: 888: 887: 875: 855: 852: 849: 827: 823: 800: 796: 775: 772: 767: 763: 759: 754: 750: 746: 741: 737: 716: 705: 692: 667: 657: 644: 623: 608: 594: 590: 568: 564: 560: 528: 514: 513: 499: 495: 491: 487: 483: 479: 454: 444: 431: 410: 395: 383: 362: 337: 327: 314: 293: 278: 265: 235: 231: 209: 205: 201: 169: 157: 154: 126: 123: 26: 9: 6: 4: 3: 2: 10797: 10786: 10783: 10781: 10778: 10776: 10773: 10772: 10770: 10755: 10754:Ernst Zermelo 10752: 10750: 10747: 10745: 10742: 10740: 10739:Willard Quine 10737: 10735: 10732: 10730: 10727: 10725: 10722: 10720: 10717: 10715: 10712: 10710: 10707: 10705: 10702: 10700: 10697: 10696: 10694: 10692: 10691:Set theorists 10688: 10682: 10679: 10677: 10674: 10672: 10669: 10668: 10666: 10660: 10658: 10655: 10654: 10651: 10643: 10640: 10638: 10637:Kripke–Platek 10635: 10631: 10628: 10627: 10626: 10623: 10622: 10621: 10618: 10614: 10611: 10610: 10609: 10608: 10604: 10600: 10597: 10596: 10595: 10592: 10591: 10588: 10585: 10583: 10580: 10578: 10575: 10573: 10570: 10569: 10567: 10563: 10557: 10554: 10552: 10549: 10547: 10544: 10542: 10540: 10535: 10533: 10530: 10528: 10525: 10522: 10518: 10515: 10513: 10510: 10506: 10503: 10501: 10498: 10496: 10493: 10492: 10491: 10488: 10485: 10481: 10478: 10476: 10473: 10471: 10468: 10466: 10463: 10462: 10460: 10457: 10453: 10447: 10444: 10442: 10439: 10437: 10434: 10432: 10429: 10427: 10424: 10422: 10419: 10417: 10414: 10410: 10407: 10405: 10402: 10401: 10400: 10397: 10395: 10392: 10390: 10387: 10385: 10382: 10380: 10377: 10374: 10370: 10367: 10365: 10362: 10360: 10357: 10356: 10354: 10348: 10345: 10344: 10341: 10335: 10332: 10330: 10327: 10325: 10322: 10320: 10317: 10315: 10312: 10310: 10307: 10305: 10302: 10299: 10296: 10294: 10291: 10290: 10288: 10286: 10282: 10274: 10273:specification 10271: 10269: 10266: 10265: 10264: 10261: 10260: 10257: 10254: 10252: 10249: 10247: 10244: 10242: 10239: 10237: 10234: 10232: 10229: 10227: 10224: 10222: 10219: 10217: 10214: 10212: 10209: 10205: 10202: 10200: 10197: 10195: 10192: 10191: 10190: 10187: 10185: 10182: 10181: 10179: 10177: 10173: 10168: 10158: 10155: 10154: 10152: 10148: 10144: 10137: 10132: 10130: 10125: 10123: 10118: 10117: 10114: 10104: 10103: 10098: 10090: 10084: 10081: 10079: 10076: 10074: 10071: 10069: 10066: 10062: 10059: 10058: 10057: 10054: 10052: 10049: 10047: 10044: 10042: 10038: 10035: 10033: 10030: 10028: 10025: 10023: 10020: 10018: 10015: 10014: 10012: 10008: 10002: 9999: 9997: 9994: 9992: 9991:Recursive set 9989: 9987: 9984: 9982: 9979: 9977: 9974: 9972: 9969: 9965: 9962: 9960: 9957: 9955: 9952: 9950: 9947: 9945: 9942: 9941: 9940: 9937: 9935: 9932: 9930: 9927: 9925: 9922: 9920: 9917: 9915: 9912: 9911: 9909: 9907: 9903: 9897: 9894: 9892: 9889: 9887: 9884: 9882: 9879: 9877: 9874: 9872: 9869: 9867: 9864: 9860: 9857: 9855: 9852: 9850: 9847: 9846: 9845: 9842: 9840: 9837: 9835: 9832: 9830: 9827: 9825: 9822: 9820: 9817: 9813: 9810: 9809: 9808: 9805: 9801: 9800:of arithmetic 9798: 9797: 9796: 9793: 9789: 9786: 9784: 9781: 9779: 9776: 9774: 9771: 9769: 9766: 9765: 9764: 9761: 9757: 9754: 9752: 9749: 9748: 9747: 9744: 9743: 9741: 9739: 9735: 9729: 9726: 9724: 9721: 9719: 9716: 9714: 9711: 9708: 9707:from ZFC 9704: 9701: 9699: 9696: 9690: 9687: 9686: 9685: 9682: 9680: 9677: 9675: 9672: 9671: 9670: 9667: 9665: 9662: 9660: 9657: 9655: 9652: 9650: 9647: 9645: 9642: 9640: 9637: 9636: 9634: 9632: 9628: 9618: 9617: 9613: 9612: 9607: 9606:non-Euclidean 9604: 9600: 9597: 9595: 9592: 9590: 9589: 9585: 9584: 9582: 9579: 9578: 9576: 9572: 9568: 9565: 9563: 9560: 9559: 9558: 9554: 9550: 9547: 9546: 9545: 9541: 9537: 9534: 9532: 9529: 9527: 9524: 9522: 9519: 9517: 9514: 9512: 9509: 9508: 9506: 9502: 9501: 9499: 9494: 9488: 9483:Example  9480: 9472: 9467: 9466: 9465: 9462: 9460: 9457: 9453: 9450: 9448: 9445: 9443: 9440: 9438: 9435: 9434: 9433: 9430: 9428: 9425: 9423: 9420: 9418: 9415: 9411: 9408: 9406: 9403: 9402: 9401: 9398: 9394: 9391: 9389: 9386: 9384: 9381: 9379: 9376: 9375: 9374: 9371: 9369: 9366: 9362: 9359: 9357: 9354: 9352: 9349: 9348: 9347: 9344: 9340: 9337: 9335: 9332: 9330: 9327: 9325: 9322: 9320: 9317: 9315: 9312: 9311: 9310: 9307: 9305: 9302: 9300: 9297: 9295: 9292: 9288: 9285: 9283: 9280: 9278: 9275: 9273: 9270: 9269: 9268: 9265: 9263: 9260: 9258: 9255: 9253: 9250: 9246: 9243: 9241: 9240:by definition 9238: 9237: 9236: 9233: 9229: 9226: 9225: 9224: 9221: 9219: 9216: 9214: 9211: 9209: 9206: 9204: 9201: 9200: 9197: 9194: 9192: 9188: 9183: 9177: 9173: 9163: 9160: 9158: 9155: 9153: 9150: 9148: 9145: 9143: 9140: 9138: 9135: 9133: 9130: 9128: 9127:Kripke–Platek 9125: 9123: 9120: 9116: 9113: 9111: 9108: 9107: 9106: 9103: 9102: 9100: 9096: 9088: 9085: 9084: 9083: 9080: 9078: 9075: 9071: 9068: 9067: 9066: 9063: 9061: 9058: 9056: 9053: 9051: 9048: 9046: 9043: 9040: 9036: 9032: 9029: 9025: 9022: 9020: 9017: 9015: 9012: 9011: 9010: 9006: 9003: 9002: 9000: 8998: 8994: 8990: 8982: 8979: 8977: 8974: 8972: 8971:constructible 8969: 8968: 8967: 8964: 8962: 8959: 8957: 8954: 8952: 8949: 8947: 8944: 8942: 8939: 8937: 8934: 8932: 8929: 8927: 8924: 8922: 8919: 8917: 8914: 8912: 8909: 8907: 8904: 8903: 8901: 8899: 8894: 8886: 8883: 8881: 8878: 8876: 8873: 8871: 8868: 8866: 8863: 8861: 8858: 8857: 8855: 8851: 8848: 8846: 8843: 8842: 8841: 8838: 8836: 8833: 8831: 8828: 8826: 8823: 8821: 8817: 8813: 8811: 8808: 8804: 8801: 8800: 8799: 8796: 8795: 8792: 8789: 8787: 8783: 8773: 8770: 8768: 8765: 8763: 8760: 8758: 8755: 8753: 8750: 8748: 8745: 8741: 8738: 8737: 8736: 8733: 8729: 8724: 8723: 8722: 8719: 8718: 8716: 8714: 8710: 8702: 8699: 8697: 8694: 8692: 8689: 8688: 8687: 8684: 8682: 8679: 8677: 8674: 8672: 8669: 8667: 8664: 8662: 8659: 8657: 8654: 8653: 8651: 8649: 8648:Propositional 8645: 8639: 8636: 8634: 8631: 8629: 8626: 8624: 8621: 8619: 8616: 8614: 8611: 8607: 8604: 8603: 8602: 8599: 8597: 8594: 8592: 8589: 8587: 8584: 8582: 8579: 8577: 8576:Logical truth 8574: 8572: 8569: 8568: 8566: 8564: 8560: 8557: 8555: 8551: 8545: 8542: 8540: 8537: 8535: 8532: 8530: 8527: 8525: 8522: 8520: 8516: 8512: 8508: 8506: 8503: 8501: 8498: 8496: 8492: 8489: 8488: 8486: 8484: 8478: 8473: 8467: 8464: 8462: 8459: 8457: 8454: 8452: 8449: 8447: 8444: 8442: 8439: 8437: 8434: 8432: 8429: 8427: 8424: 8422: 8419: 8417: 8414: 8412: 8409: 8405: 8402: 8401: 8400: 8397: 8396: 8394: 8390: 8386: 8379: 8374: 8372: 8367: 8365: 8360: 8359: 8356: 8344: 8336: 8334: 8331: 8330: 8327: 8321: 8318: 8316: 8313: 8310: 8306: 8300: 8296: 8291: 8289: 8286: 8284: 8283:Fuzzy numbers 8281: 8279: 8276: 8275: 8273: 8269: 8263: 8260: 8258: 8255: 8253: 8250: 8248: 8245: 8243: 8240: 8238: 8235: 8233: 8230: 8226: 8223: 8222: 8221: 8218: 8216: 8213: 8211: 8208: 8207: 8205: 8203: 8199: 8195: 8187: 8184: 8182: 8179: 8177: 8174: 8173: 8172: 8168: 8165: 8163: 8160: 8158: 8155: 8130: 8127: 8125: 8122: 8120: 8117: 8115: 8112: 8110: 8107: 8106: 8104: 8102: 8097: 8091: 8088: 8086: 8085:Biquaternions 8083: 8081: 8078: 8052: 8049: 8047: 8044: 8042: 8039: 8014: 8013: 8011: 8005: 7976: 7973: 7948: 7945: 7920: 7917: 7892: 7888: 7885: 7884: 7882: 7880: 7876: 7870: 7867: 7863: 7860: 7859: 7858: 7855: 7853: 7850: 7848: 7845: 7843: 7840: 7813: 7810: 7808: 7805: 7780: 7777: 7775: 7772: 7747: 7744: 7719: 7716: 7691: 7688: 7687: 7685: 7683: 7678: 7673: 7666: 7661: 7659: 7654: 7652: 7647: 7646: 7643: 7636: 7631: 7626: 7624: 7614: 7613: 7610: 7601: 7595: 7591: 7587: 7583: 7579: 7574: 7571: 7569:0-07-054235-X 7565: 7561: 7557: 7556:Rudin, Walter 7553: 7550: 7548:0-387-94001-4 7544: 7540: 7536: 7532: 7529: 7523: 7519: 7515: 7511: 7508: 7504: 7500: 7499:0-387-90092-6 7496: 7490: 7489: 7484: 7480: 7477: 7475:0-87150-164-3 7471: 7467: 7462: 7459: 7453: 7449: 7444: 7441: 7437: 7433: 7429: 7425: 7421: 7417: 7412: 7409: 7407:0-673-38152-8 7403: 7399: 7394: 7391: 7385: 7380: 7379: 7374:(June 1969), 7373: 7369: 7368: 7355: 7349: 7345: 7344: 7336: 7330:, p. 187 7329: 7324: 7318:, p. 180 7317: 7312: 7305: 7300: 7294:, p. 182 7293: 7288: 7281: 7276: 7269: 7264: 7256: 7252: 7248: 7242: 7233: 7224: 7217: 7212: 7210:9781439865507 7206: 7202: 7201: 7196: 7190: 7184:, p. 182 7183: 7178: 7170: 7164: 7160: 7159: 7151: 7144: 7139: 7132: 7127: 7119: 7113: 7110:. CRC Press. 7109: 7108: 7100: 7098: 7089: 7083: 7079: 7078: 7070: 7062: 7056: 7052: 7051: 7043: 7041: 7039: 7030: 7024: 7020: 7019: 7011: 7003: 6997: 6993: 6992: 6984: 6977: 6972: 6965: 6960: 6958: 6950: 6945: 6939:, p. 181 6938: 6933: 6926: 6921: 6913: 6907: 6903: 6902: 6894: 6890: 6876: 6872: 6866: 6860:is countable. 6847: 6827: 6816: 6813: 6810: 6807: 6787: 6767: 6747: 6741: 6738: 6735: 6715: 6704: 6701: 6681: 6661: 6641: 6613: 6610: 6607: 6604: 6601: 6581: 6575: 6572: 6569: 6541: 6538: 6535: 6515: 6507: 6502: 6481: 6477: 6471: 6468: 6465: 6461: 6449: 6441: 6438: 6416: 6412: 6367: 6363: 6355:a surjection 6320: 6312: 6291: 6288: 6280: 6275: 6269:is countable. 6254: 6250: 6244: 6241: 6238: 6234: 6208: 6205: 6182: 6174: 6170: 6166: 6160: 6157: 6154: 6148: 6128: 6123: 6119: 6113: 6110: 6107: 6103: 6091: 6088: 6085: 6082: 6060: 6056: 6044: 6039: 6035: 6014: 5991: 5988: 5985: 5982: 5979: 5973: 5970: 5950: 5928: 5924: 5915: 5910: 5903: 5887: 5865: 5861: 5836: 5832: 5824: 5821: 5818: 5814: 5808: 5801: 5797: 5792: 5788: 5781: 5777: 5772: 5768: 5761: 5757: 5752: 5748: 5743: 5740: 5737: 5733: 5729: 5723: 5717: 5684: 5681: 5661: 5641: 5619: 5615: 5609: 5605: 5601: 5598: 5595: 5590: 5586: 5580: 5576: 5572: 5567: 5563: 5557: 5553: 5549: 5544: 5540: 5534: 5530: 5509: 5501: 5496: 5450: 5422: 5419: 5416: 5409: 5405: 5402: 5396: 5393: 5390: 5384: 5351: 5343: 5340: 5298: 5276: 5273: 5269: 5265: 5259: 5253: 5233: 5211: 5207: 5203: 5197: 5191: 5158: 5155: 5126:The integers 5125: 5120: 5113: 5097: 5094: 5091: 5071: 5068: 5065: 5040: 5015: 5012: 5009: 4998: 4990: 4987: 4984: 4981: 4961: 4950: 4947: 4927: 4916: 4913: 4893: 4873: 4851: 4847: 4843: 4838: 4834: 4830: 4824: 4821: 4818: 4812: 4779: 4771: 4768: 4743: 4731:Observe that 4730: 4725: 4718: 4714: 4695: 4692: 4689: 4686: 4683: 4680: 4677: 4671: 4666: 4629: 4623: 4621: 4616: 4606: 4603: 4601: 4598: 4596: 4593: 4591: 4588: 4587: 4581: 4579: 4578:least element 4575: 4571: 4570:least element 4561: 4558: 4557: 4555: 4551: 4546: 4543: 4542: 4540: 4536: 4533: 4532: 4531: 4529: 4519: 4517: 4513: 4508: 4506: 4498: 4494: 4491: 4487: 4486: 4485: 4483: 4479: 4475: 4471: 4461: 4459: 4455: 4450: 4448: 4442: 4440: 4393: 4391: 4372: 4342: 4322: 4314: 4295: 4278:is a set and 4265: 4257: 4256: 4251: 4245:is countable. 4232: 4212: 4192: 4186: 4183: 4180: 4172: 4170:is countable. 4157: 4137: 4117: 4111: 4108: 4105: 4097: 4096: 4095: 4081: 4061: 4045: 4041: 4039: 4027: 4022: 4020: 4008: 3994: 3991: 3981: 3971: 3956: 3952: 3947: 3928: 3919: 3902: 3899: 3896: 3888: 3879: 3862: 3859: 3856: 3848: 3839: 3822: 3819: 3816: 3808: 3799: 3782: 3779: 3776: 3768: 3759: 3742: 3739: 3736: 3728: 3719: 3702: 3699: 3696: 3688: 3679: 3662: 3659: 3656: 3648: 3639: 3622: 3619: 3616: 3608: 3599: 3582: 3579: 3576: 3568: 3559: 3542: 3539: 3536: 3528: 3519: 3502: 3499: 3496: 3488: 3441: 3438: 3428: 3418: 3398: 3393: 3391: 3379: 3374: 3372: 3360: 3343: 3340: 3337: 3314: 3310: 3306: 3298: 3282: 3262: 3242: 3222: 3213: 3211: 3205: 3152: 3138: 3134: 3130: 3110: 3090: 3087: 3084: 3064: 3044: 3040: 3036: 3028: 3024: 3020: 2973: 2948: 2942: 2940: 2928: 2914: 2872: 2849: 2846: 2843: 2817: 2814: 2811: 2785: 2782: 2779: 2753: 2750: 2744: 2741: 2738: 2725:maps to 5 so 2709: 2706: 2703: 2677: 2674: 2668: 2665: 2662: 2633: 2630: 2627: 2624: 2621: 2598: 2578: 2556: 2552: 2526: 2522: 2518: 2515: 2512: 2507: 2503: 2499: 2494: 2490: 2486: 2481: 2477: 2465: 2449: 2441: 2436: 2422: 2419: 2413: 2410: 2407: 2398: 2395: 2389: 2386: 2383: 2374: 2371: 2365: 2362: 2359: 2350: 2347: 2341: 2338: 2335: 2326: 2323: 2317: 2314: 2311: 2302: 2299: 2293: 2290: 2287: 2278: 2275: 2269: 2266: 2263: 2254: 2246: 2244: 2236: 2231: 2227: 2208: 2195: 2191: 2190:ordered pairs 2185: 2175: 2157: 2152: 2149: 2143: 2138: 2135: 2129: 2124: 2121: 2115: 2110: 2107: 2101: 2096: 2093: 2087: 2080: 2075: 2072: 2066: 2061: 2058: 2052: 2047: 2044: 2038: 2033: 2030: 2024: 2019: 2016: 2010: 1986: 1983: 1977: 1957: 1954: 1951: 1945: 1922: 1919: 1916: 1913: 1910: 1907: 1904: 1901: 1898: 1892: 1889: 1881: 1862: 1859: 1856: 1853: 1850: 1847: 1844: 1838: 1835: 1793: 1785: 1769: 1760: 1746: 1738: 1719: 1716: 1713: 1710: 1707: 1696: 1695:precisely one 1677: 1674: 1671: 1668: 1665: 1659: 1656: 1636: 1630: 1624: 1621: 1615: 1609: 1606: 1600: 1577: 1574: 1571: 1568: 1565: 1562: 1559: 1553: 1541: 1525: 1517: 1513: 1497: 1483: 1480: 1476: 1460: 1447: 1442: 1438: 1437: 1432: 1416: 1413: 1407: 1387: 1383: 1375: 1371: 1368: 1360: 1356: 1353: 1345: 1341: 1338: 1334: 1326: 1322: 1318: 1315: 1311: 1303: 1299: 1295: 1272: 1269: 1266: 1263: 1260: 1257: 1254: 1251: 1248: 1245: 1242: 1239: 1236: 1213: 1191: 1187: 1183: 1180: 1160: 1140: 1120: 1112: 1103: 1099: 1085: 1065: 1057: 1053: 1034: 1031: 1028: 1025: 1022: 1019: 1016: 1013: 1010: 984: 981: 978: 975: 972: 961: 957: 956: 945: 943: 938: 934: 924: 908: 895: 894: 873: 853: 850: 847: 825: 821: 798: 794: 773: 770: 765: 761: 757: 752: 748: 744: 739: 735: 714: 706: 681: 665: 658: 621: 613: 609: 592: 562: 549: 548: 547: 545: 544: 526: 517: 497: 489: 481: 468: 452: 445: 408: 400: 396: 381: 351: 335: 328: 291: 283: 279: 255: 251: 233: 203: 191: 187: 186: 185: 183: 167: 153: 151: 147: 143: 138: 136: 132: 122: 120: 116: 112: 107: 105: 101: 97: 93: 88: 85: 81: 77: 73: 69: 65: 61: 57: 49: 42: 38: 34: 19: 10704:Georg Cantor 10699:Paul Bernays 10630:Morse–Kelley 10605: 10538: 10537:Subset  10484:hereditarily 10469: 10446:Venn diagram 10404:ordered pair 10319:Intersection 10263:Axiom schema 10093: 9891:Ultraproduct 9738:Model theory 9703:Independence 9639:Formal proof 9631:Proof theory 9614: 9587: 9544:real numbers 9516:second-order 9427:Substitution 9304:Metalanguage 9245:conservative 9218:Axiom schema 9162:Constructive 9132:Morse–Kelley 9098:Set theories 9077:Aleph number 9070:inaccessible 8976:Grothendieck 8905: 8860:intersection 8747:Higher-order 8735:Second-order 8681:Truth tables 8638:Venn diagram 8421:Formal proof 8304: 8294: 8109:Dual numbers 8101:hypercomplex 7891:Real numbers 7581: 7559: 7538: 7517: 7514:Kamke, Erich 7487: 7465: 7447: 7423: 7419: 7397: 7377: 7342: 7335: 7323: 7311: 7299: 7287: 7282:, p. 92 7275: 7270:, p. 91 7263: 7250: 7241: 7232: 7223: 7214: 7199: 7189: 7177: 7157: 7150: 7138: 7126: 7106: 7076: 7069: 7049: 7017: 7010: 6990: 6983: 6976:Apostol 1969 6971: 6944: 6932: 6920: 6900: 6893: 6865: 6505: 6501: 6278: 6274: 5913: 5909: 5499: 5495: 5123: 5119: 4728: 4724: 4590:Aleph number 4577: 4573: 4569: 4567: 4553: 4525: 4522:Total orders 4509: 4502: 4496: 4489: 4481: 4467: 4454:real numbers 4451: 4444: 4395: 4253: 4252: 4249: 4047: 4043: 4029: 4024: 4010: 3954: 3949:We need the 3948: 3403: 3381: 3376: 3362: 3214: 3207: 3154: 2944: 2930: 2437: 2247: 2240: 2187: 2177: 1761: 1736: 1694: 1511: 1489: 1479:Georg Cantor 1477: 1445: 1434: 1430: 1173:is, such as 1110: 1108: 1055: 959: 953: 951: 948:Introduction 937:real numbers 931:In 1874, in 930: 891: 889: 540: 518: 515: 181: 159: 145: 141: 139: 134: 130: 128: 119:real numbers 111:Georg Cantor 108: 103: 95: 89: 79: 63: 53: 10729:Thomas Jech 10572:Alternative 10551:Uncountable 10505:Ultrafilter 10364:Cardinality 10268:replacement 10216:Determinacy 10001:Type theory 9949:undecidable 9881:Truth value 9768:equivalence 9447:non-logical 9060:Enumeration 9050:Isomorphism 8997:cardinality 8981:Von Neumann 8946:Ultrafilter 8911:Uncountable 8845:equivalence 8762:Quantifiers 8752:Fixed-point 8721:First-order 8601:Consistency 8586:Proposition 8563:Traditional 8534:Lindström's 8524:Compactness 8466:Type theory 8411:Cardinality 8271:Other types 8090:Bioctonions 7947:Quaternions 7635:Mathematics 7535:Lang, Serge 7280:Halmos 1960 7268:Halmos 1960 7131:Halmos 1960 6951:, p. 2 6927:, Chapter 2 6873:, and also 6728:. Then if 6562:. Then if 5058:to the set 4535:Well-orders 4488:subsets of 4470:inner model 4452:The set of 4439:uncountable 4397:Proposition 3369:Any finite 3023:denominator 2440:recursively 1806:and all of 1697:element of 893:uncountable 580:is exactly 190:cardinality 146:denumerable 100:cardinality 94:, a set is 56:mathematics 10769:Categories 10724:Kurt Gödel 10709:Paul Cohen 10546:Transitive 10314:Identities 10298:Complement 10285:Operations 10246:Regularity 10184:Adjunction 10143:Set theory 9812:elementary 9505:arithmetic 9373:Quantifier 9351:functional 9223:Expression 8941:Transitive 8885:identities 8870:complement 8803:hereditary 8786:Set theory 8225:Projective 8198:Infinities 7623:Arithmetic 7582:Analysis I 7365:References 7304:Kamke 1950 7143:Kamke 1950 6949:Kamke 1950 6925:Rudin 1976 4537:(see also 4507:for more. 1999:, so that 886:is listed. 541:countably 465:is either 250:aleph-null 156:Definition 142:enumerable 140:The terms 37:Count data 33:Count noun 10657:Paradoxes 10577:Axiomatic 10556:Universal 10532:Singleton 10527:Recursive 10470:Countable 10465:Amorphous 10324:Power set 10241:Power set 10199:dependent 10194:countable 10083:Supertask 9986:Recursion 9944:decidable 9778:saturated 9756:of models 9679:deductive 9674:axiomatic 9594:Hilbert's 9581:Euclidean 9562:canonical 9485:axiomatic 9417:Signature 9346:Predicate 9235:Extension 9157:Ackermann 9082:Operation 8961:Universal 8951:Recursive 8926:Singleton 8921:Inhabited 8906:Countable 8896:Types of 8880:power set 8850:partition 8767:Predicate 8713:Predicate 8628:Syllogism 8618:Soundness 8591:Inference 8581:Tautology 8483:paradoxes 8309:solenoids 8129:Sedenions 7975:Octonions 7440:123695365 6964:Lang 1993 6885:Citations 6825:→ 6811:∘ 6745:→ 6713:→ 6617:→ 6605:∘ 6579:→ 6545:→ 6469:∈ 6462:⋃ 6458:→ 6450:× 6242:∈ 6235:⋃ 6209:× 6141:given by 6111:∈ 6104:⋃ 6100:→ 6092:× 6053:→ 5986:… 5809:⋯ 5789:⋅ 5769:⋅ 5749:⋅ 5741:− 5724:α 5710:given by 5693:→ 5642:α 5599:⋯ 5510:α 5451:× 5377:given by 5360:→ 5352:× 5274:− 5184:given by 5167:→ 5112:induction 5095:× 5069:× 5041:× 5013:× 5007:→ 4999:× 4985:× 4959:→ 4925:→ 4844:⋅ 4805:given by 4788:→ 4780:× 4744:× 4713:ISO 31-11 4696:… 4667:∗ 4628:bijection 4458:sequences 4313:power set 4190:→ 4115:→ 4094:be sets. 4019:sequences 3995:… 3957:the sets 3953:to index 3929:⋮ 3442:… 3088:≠ 3019:numerator 2516:… 2423:… 2402:↔ 2378:↔ 2354:↔ 2330:↔ 2306:↔ 2282:↔ 2258:↔ 2209:× 2158:… 2147:↔ 2133:↔ 2119:↔ 2105:↔ 2091:↔ 2081:… 2070:↔ 2056:↔ 2042:↔ 2028:↔ 2014:↔ 1981:↔ 1949:↔ 1923:… 1863:… 1784:bijection 1634:↔ 1619:↔ 1604:↔ 1578:… 1516:bijection 1512:countable 1457:ℵ 1436:bijection 1411:→ 1388:⋯ 1380:→ 1365:→ 1350:→ 1335:− 1331:→ 1323:− 1312:− 1308:→ 1300:− 1296:… 1273:… 1029:… 905:ℵ 890:A set is 851:≠ 774:… 612:bijective 589:ℵ 494:ℵ 399:bijective 230:ℵ 182:countable 131:countable 96:countable 80:countable 64:countable 10785:Infinity 10661:Problems 10565:Theories 10541:Superset 10517:Infinite 10346:Concepts 10226:Infinity 10150:Overview 10068:Logicism 10061:timeline 10037:Concrete 9896:Validity 9866:T-schema 9859:Kripke's 9854:Tarski's 9849:semantic 9839:Strength 9788:submodel 9783:spectrum 9751:function 9599:Tarski's 9588:Elements 9575:geometry 9531:Robinson 9452:variable 9437:function 9410:spectrum 9400:Sentence 9356:variable 9299:Language 9252:Relation 9213:Automata 9203:Alphabet 9187:language 9041:-jection 9019:codomain 9005:Function 8966:Universe 8936:Infinite 8840:Relation 8623:Validity 8613:Argument 8511:theorem, 7718:Integers 7680:Sets of 7558:(1976), 7537:(1993), 7516:(1950), 7485:(1960), 7255:Archived 7197:(2010), 7182:Tao 2016 6937:Tao 2016 6901:Topology 5853:, where 4630:between 4595:Counting 4584:See also 4402:The set 3327:maps to 2947:integers 2769:maps to 1880:integers 1786:between 1518:between 1441:function 1111:infinite 1056:possible 1052:integers 960:elements 942:ordinals 786:, where 543:infinite 10599:General 10594:Zermelo 10500:subbase 10482: ( 10421:Forcing 10399:Element 10371: ( 10349:Methods 10236:Pairing 10010:Related 9807:Diagram 9705: ( 9684:Hilbert 9669:Systems 9664:Theorem 9542:of the 9487:systems 9267:Formula 9262:Grammar 9178: ( 9122:General 8835:Forcing 8820:Element 8740:Monadic 8515:paradox 8456:Theorem 8392:General 8299:numbers 8131: ( 7977: ( 7949: ( 7921: ( 7893: ( 7814: ( 7812:Periods 7781: ( 7748: ( 7720: ( 7692: ( 7674:systems 7609:Portals 7133:, p. 91 5880:is the 5654:is the 4552:Other ( 4476:). The 4311:is its 4049:Theorem 4038:subsets 4031:Theorem 4012:Theorem 3481:Element 3383:Theorem 3364:Theorem 3255:, then 3156:Theorem 2932:Theorem 2801:, then 2693:. Then 2243:mapping 2179:Theorem 927:History 98:if its 10490:Filter 10480:Finite 10416:Family 10359:Almost 10204:global 10189:Choice 10176:Axioms 9773:finite 9536:Skolem 9489:  9464:Theory 9432:Symbol 9422:String 9405:atomic 9282:ground 9277:closed 9272:atomic 9228:ground 9191:syntax 9087:binary 9014:domain 8931:Finite 8696:finite 8554:Logics 8513:  8461:Theory 8099:Other 7672:Number 7596:  7566:  7545:  7524:  7505:  7497:  7472:  7454:  7438:  7404:  7386:  7350:  7207:  7165:  7145:, p. 2 7114:  7084:  7057:  7025:  6998:  6908:  5914:Proof: 5522:, let 5500:Proof: 5124:Proof: 4729:Proof: 3057:where 2544:where 2464:tuples 1882:, and 1628:  1613:  678:has a 519:A set 467:finite 160:A set 68:finite 10582:Naive 10512:Fuzzy 10475:Empty 10458:types 10409:tuple 10379:Class 10373:large 10334:Union 10251:Union 9763:Model 9511:Peano 9368:Proof 9208:Arity 9137:Naive 9024:image 8956:Fuzzy 8916:Empty 8865:union 8810:Class 8451:Model 8441:Lemma 8399:Axiom 8307:-adic 8297:-adic 8054:Over 8015:Over 8009:types 8007:Split 7436:S2CID 7251:expii 6506:Proof 6279:Proof 5902:prime 4974:. So 4611:Notes 3474:Tuple 3467:Index 3371:union 3025:of a 682:with 352:from 284:from 10495:base 9886:Type 9689:list 9493:list 9470:list 9459:Term 9393:rank 9287:open 9181:list 8993:Maps 8898:sets 8757:Free 8727:list 8477:list 8404:list 8343:List 8200:and 7594:ISBN 7564:ISBN 7543:ISBN 7522:ISBN 7503:ISBN 7495:ISBN 7470:ISBN 7452:ISBN 7424:1878 7402:ISBN 7384:ISBN 7348:ISBN 7205:ISBN 7163:ISBN 7112:ISBN 7082:ISBN 7055:ISBN 7023:ISBN 6996:ISBN 6906:ISBN 6869:See 6780:and 5900:-th 4940:and 4886:and 4652:and 4574:some 4074:and 4054:Let 3077:and 3021:and 2937:The 2571:and 2233:The 1970:and 1433:(or 1192:1000 840:for 634:and 546:if: 490:< 188:Its 184:if: 144:and 58:, a 10456:Set 9573:of 9555:of 9503:of 9035:Sur 9009:Map 8816:Ur- 8798:Set 7586:doi 7428:doi 6404:to 6333:in 5963:in 5916:If 5291:if 5226:if 4554:not 4541:): 4355:to 3955:all 1737:and 1510:is 1098:". 1035:100 955:set 539:is 374:to 304:to 180:is 62:is 60:set 54:In 10771:: 9959:NP 9583:: 9577:: 9507:: 9184:), 9039:Bi 9031:In 7889:: 7592:. 7580:. 7434:, 7422:, 7418:, 7249:. 7213:, 7096:^ 7037:^ 6956:^ 4619:^ 4449:. 4441:. 3889:10 1735:, 1475:. 1188:10 952:A 923:. 152:. 121:. 106:. 10539:· 10523:) 10519:( 10486:) 10375:) 10135:e 10128:t 10121:v 10039:/ 9954:P 9709:) 9495:) 9491:( 9388:∀ 9383:! 9378:∃ 9339:= 9334:↔ 9329:→ 9324:∧ 9319:√ 9314:ÂŹ 9037:/ 9033:/ 9007:/ 8818:) 8814:( 8701:∞ 8691:3 8479:) 8377:e 8370:t 8363:v 8311:) 8305:p 8301:( 8295:p 8169:/ 8153:) 8140:S 8076:: 8063:C 8037:: 8024:R 7999:) 7986:O 7971:) 7958:H 7943:) 7930:C 7915:) 7902:R 7838:) 7824:P 7803:) 7790:A 7770:) 7757:Q 7742:) 7729:Z 7714:) 7701:N 7664:e 7657:t 7650:v 7611:: 7602:. 7588:: 7430:: 7356:. 7171:. 7120:. 7090:. 7063:. 7031:. 7004:. 6914:. 6848:T 6828:T 6821:N 6817:: 6814:h 6808:g 6788:T 6768:S 6748:T 6742:S 6739:: 6736:g 6716:S 6709:N 6705:: 6702:h 6682:S 6662:S 6642:S 6621:N 6614:S 6611:: 6608:f 6602:h 6582:T 6576:S 6573:: 6570:f 6549:N 6542:T 6539:: 6536:h 6516:T 6482:i 6478:A 6472:I 6466:i 6454:N 6446:N 6442:: 6439:G 6417:i 6413:A 6391:N 6368:i 6364:g 6342:N 6321:i 6296:N 6292:= 6289:I 6255:i 6251:A 6245:I 6239:i 6213:N 6206:I 6186:) 6183:m 6180:( 6175:i 6171:g 6167:= 6164:) 6161:m 6158:, 6155:i 6152:( 6149:G 6129:, 6124:i 6120:A 6114:I 6108:i 6096:N 6089:I 6086:: 6083:G 6061:i 6057:A 6049:N 6045:: 6040:i 6036:g 6015:i 5995:} 5992:n 5989:, 5983:, 5980:1 5977:{ 5974:= 5971:I 5951:i 5929:i 5925:A 5904:. 5888:n 5866:n 5862:p 5837:n 5833:a 5825:2 5822:+ 5819:n 5815:p 5802:2 5798:a 5793:7 5782:1 5778:a 5773:5 5762:0 5758:a 5753:3 5744:1 5738:k 5734:2 5730:= 5727:) 5721:( 5718:f 5697:Q 5689:A 5685:: 5682:f 5662:k 5620:n 5616:x 5610:n 5606:a 5602:+ 5596:+ 5591:2 5587:x 5581:2 5577:a 5573:+ 5568:1 5564:x 5558:1 5554:a 5550:+ 5545:0 5541:x 5535:0 5531:a 5490:. 5477:Q 5455:N 5447:Z 5426:) 5423:1 5420:+ 5417:n 5414:( 5410:/ 5406:m 5403:= 5400:) 5397:n 5394:, 5391:m 5388:( 5385:g 5364:Q 5356:N 5348:Z 5344:: 5341:g 5320:Q 5299:n 5277:n 5270:3 5266:= 5263:) 5260:n 5257:( 5254:f 5234:n 5212:n 5208:2 5204:= 5201:) 5198:n 5195:( 5192:f 5171:N 5163:Z 5159:: 5156:f 5135:Z 5098:B 5092:A 5072:B 5066:A 5045:N 5037:N 5016:B 5010:A 5003:N 4995:N 4991:: 4988:g 4982:f 4962:B 4955:N 4951:: 4948:g 4928:A 4921:N 4917:: 4914:f 4894:B 4874:A 4852:n 4848:3 4839:m 4835:2 4831:= 4828:) 4825:n 4822:, 4819:m 4816:( 4813:f 4792:N 4784:N 4776:N 4772:: 4769:f 4748:N 4740:N 4699:} 4693:, 4690:3 4687:, 4684:2 4681:, 4678:1 4675:{ 4672:= 4662:N 4639:N 4499:, 4497:M 4490:M 4482:M 4425:) 4421:N 4417:( 4412:P 4376:) 4373:A 4370:( 4365:P 4343:A 4323:A 4299:) 4296:A 4293:( 4288:P 4266:A 4233:T 4213:S 4193:T 4187:S 4184:: 4181:g 4158:S 4138:T 4118:T 4112:S 4109:: 4106:f 4082:T 4062:S 3992:, 3987:c 3982:, 3977:b 3972:, 3967:a 3920:4 3914:a 3906:) 3903:4 3900:, 3897:0 3894:( 3880:0 3874:d 3866:) 3863:0 3860:, 3857:3 3854:( 3849:9 3840:1 3834:c 3826:) 3823:1 3820:, 3817:2 3814:( 3809:8 3800:2 3794:b 3786:) 3783:2 3780:, 3777:1 3774:( 3769:7 3760:3 3754:a 3746:) 3743:3 3740:, 3737:0 3734:( 3729:6 3720:0 3714:c 3706:) 3703:0 3700:, 3697:2 3694:( 3689:5 3680:1 3674:b 3666:) 3663:1 3660:, 3657:1 3654:( 3649:4 3640:2 3634:a 3626:) 3623:2 3620:, 3617:0 3614:( 3609:3 3600:0 3594:b 3586:) 3583:0 3580:, 3577:1 3574:( 3569:2 3560:1 3554:a 3546:) 3543:1 3540:, 3537:0 3534:( 3529:1 3520:0 3514:a 3506:) 3503:0 3500:, 3497:0 3494:( 3489:0 3439:, 3434:c 3429:, 3424:b 3419:, 3414:a 3347:) 3344:q 3341:, 3338:p 3335:( 3315:q 3311:/ 3307:p 3283:B 3263:A 3243:B 3223:A 3191:Q 3169:Z 3139:1 3135:/ 3131:n 3111:n 3091:0 3085:b 3065:a 3045:b 3041:/ 3037:a 3004:N 2982:Q 2957:Z 2915:n 2894:N 2873:n 2853:) 2850:b 2847:, 2844:a 2841:( 2821:) 2818:3 2815:, 2812:5 2809:( 2789:) 2786:3 2783:, 2780:5 2777:( 2757:) 2754:3 2751:, 2748:) 2745:2 2742:, 2739:0 2736:( 2733:( 2713:) 2710:2 2707:, 2704:0 2701:( 2681:) 2678:3 2675:, 2672:) 2669:2 2666:, 2663:0 2660:( 2657:( 2637:) 2634:3 2631:, 2628:2 2625:, 2622:0 2619:( 2599:n 2579:n 2557:i 2553:a 2532:) 2527:n 2523:a 2519:, 2513:, 2508:3 2504:a 2500:, 2495:2 2491:a 2487:, 2482:1 2478:a 2474:( 2462:- 2450:n 2420:, 2417:) 2414:0 2411:, 2408:3 2405:( 2399:6 2396:, 2393:) 2390:2 2387:, 2384:0 2381:( 2375:5 2372:, 2369:) 2366:1 2363:, 2360:1 2357:( 2351:4 2348:, 2345:) 2342:0 2339:, 2336:2 2333:( 2327:3 2324:, 2321:) 2318:1 2315:, 2312:0 2309:( 2303:2 2300:, 2297:) 2294:0 2291:, 2288:1 2285:( 2279:1 2276:, 2273:) 2270:0 2267:, 2264:0 2261:( 2255:0 2213:N 2205:N 2153:, 2150:8 2144:4 2139:, 2136:6 2130:3 2125:, 2122:4 2116:2 2111:, 2108:2 2102:1 2097:, 2094:0 2088:0 2076:, 2073:5 2067:4 2062:, 2059:4 2053:3 2048:, 2045:3 2039:2 2034:, 2031:2 2025:1 2020:, 2017:1 2011:0 1987:n 1984:2 1978:n 1958:1 1955:+ 1952:n 1946:n 1926:} 1920:, 1917:6 1914:, 1911:4 1908:, 1905:2 1902:, 1899:0 1896:{ 1893:= 1890:B 1866:} 1860:, 1857:3 1854:, 1851:2 1848:, 1845:1 1842:{ 1839:= 1836:A 1815:N 1794:S 1770:S 1747:S 1723:} 1720:3 1717:, 1714:2 1711:, 1708:1 1705:{ 1681:} 1678:c 1675:, 1672:b 1669:, 1666:a 1663:{ 1660:= 1657:S 1637:3 1631:c 1625:, 1622:2 1616:b 1610:, 1607:1 1601:a 1581:} 1575:, 1572:2 1569:, 1566:1 1563:, 1560:0 1557:{ 1554:= 1550:N 1526:S 1498:S 1461:0 1417:n 1414:2 1408:n 1384:4 1376:2 1372:, 1369:2 1361:1 1357:, 1354:0 1346:0 1342:, 1339:2 1327:1 1319:, 1316:4 1304:2 1276:} 1270:, 1267:5 1264:, 1261:4 1258:, 1255:3 1252:, 1249:2 1246:, 1243:1 1240:, 1237:0 1234:{ 1214:n 1184:= 1181:n 1161:n 1141:n 1121:n 1086:n 1066:n 1038:} 1032:, 1026:, 1023:3 1020:, 1017:2 1014:, 1011:1 1008:{ 988:} 985:5 982:, 979:4 976:, 973:3 970:{ 909:0 874:S 854:j 848:i 826:j 822:a 799:i 795:a 771:, 766:2 762:a 758:, 753:1 749:a 745:, 740:0 736:a 715:S 704:. 691:N 666:S 656:. 643:N 622:S 607:. 593:0 567:| 563:S 559:| 527:S 498:0 486:| 482:S 478:| 469:( 453:S 443:. 430:N 409:S 394:. 382:S 361:N 336:S 326:. 313:N 292:S 277:. 264:N 248:( 234:0 208:| 204:S 200:| 168:S 50:. 43:. 20:)

Index

Countably infinite
Count noun
Count data
Countable (app)
(recursively) enumerable sets
mathematics
set
finite
one to one correspondence
natural numbers
injective function
axiom of countable choice
cardinality
Georg Cantor
uncountable sets
real numbers
recursively enumerable
cardinality
aleph-null
natural numbers
injective function
surjective function
bijective
finite
infinite
bijective
one-to-one correspondence
uncountable
his first set theory article
real numbers

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