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Well-founded relation

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in the domain of the relation. Every reflexive relation on a nonempty domain has infinite descending chains, because any constant sequence is a descending chain. For example, in the natural numbers with their usual order ≀, we have
2674: 1635: 1249: 1520: 1476: 3189:. To avoid these trivial descending sequences, when working with a partial order ≀, it is common to apply the definition of well foundedness (perhaps implicitly) to the alternate relation < defined such that 1432: 1657:
indicates that the property is not guaranteed in general (it might, or might not, hold). For example, that every equivalence relation is symmetric, but not necessarily antisymmetric, is indicated by
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is an infinite descending chain. This relation fails to be well-founded even though the entire set has a minimum element, namely the empty string.
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There are other interesting special cases of well-founded induction. When the well-founded relation is the usual ordering on the class of all
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implies that set membership is a universal among the extensional well-founded relations: for any set-like well-founded relation
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are all finite, but this does not mean that their lengths are necessarily bounded. Consider the following example: Let
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is a well-founded set, but there are descending chains starting at ω of arbitrary great (finite) length; the chain
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be the union of the positive integers with a new element ω that is bigger than any integer. Then
1386:{\displaystyle {\begin{aligned}a\neq {}&b\Rightarrow \\aRb{\text{ or }}&bRa\end{aligned}}} 5778: 5631: 5540: 5530: 5471: 5389: 5156: 4925: 4888: 4873: 4866: 4849: 4635: 4501: 4427: 4410: 4363: 4176: 4085: 3919: 3904: 3864: 3816: 3801: 3789: 3745: 3720: 3490: 3439: 3165: 3117: 2785: 1854: 1128: 1123: 1103: 1093: 1019: 121: 116: 96: 86: 5851: 5691: 5325: 4653: 4109: 1315:{\displaystyle {\begin{aligned}aRb{\text{ and }}&bRa\\\Rightarrow a={}&b\end{aligned}}} 5788: 5766: 5626: 5611: 5591: 5394: 5091: 4898: 4708: 4698: 4590: 4471: 4306: 4282: 4063: 4047: 3952: 3929: 3806: 3775: 3740: 3635: 3470: 3399: 3374: 3328: 3276: 2913: 2185: 2036: 1850: 1653:
indicates that the column's property is always true the row's term (at the very left), while
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Every class whose elements are sets, with the relation ∈ ("is an element of"). This is the
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A term's definition may require additional properties that are not listed in this table.
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An important reason that well-founded relations are interesting is because a version of
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The set of strings over a finite alphabet with more than one element, under the usual (
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On par with induction, well-founded relations also support construction of objects by
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Well-founded induction is sometimes called Noetherian induction, after
1471:{\displaystyle {\begin{aligned}a\vee b\\{\text{exists}}\end{aligned}}} 3408: 1864: 1427:{\displaystyle {\begin{aligned}\min S\\{\text{exists}}\end{aligned}}} 30:"Noetherian induction" redirects here. For the use in topology, see 4262: 3608: 3453: 2039:, i.e., that the elements less than any given element form a set. 5170: 5166: 3412: 3297:"Infinite Sequence Property of Strictly Well-Founded Relation" 2831:
Well-founded relations that are not totally ordered include:
3223:≀, it is common to use the relation < defined such that 3026:
Examples of relations that are not well-founded include:
2050:, which can be proved when there is no infinite sequence 3395:, 3rd edition, "Well-founded relations", pages 251–5, 2590: 2336: 1922: 1793: 1767: 1741: 1706: 1682: 1588: 1556: 1529: 1485: 1441: 1400: 1329: 1258: 1202: 1172: 1146: 5712: 5640: 5579: 5349: 5278: 5227: 5064: 4959: 4791: 4684: 4536: 4229: 4152: 4046: 3950: 3839: 3766: 3701: 3616: 3607: 3529: 3446: 2723:As an example, consider the well-founded relation 2668: 2475: 2023: 1808: 1779: 1753: 1727: 1688: 1629: 1573: 1541: 1514: 1470: 1426: 1385: 1314: 1243: 1187: 1158: 3275:(2nd, rev. ed.). New York: Springer-Verlag. 2881:over a fixed alphabet, with the order defined by 2046:, a relation is well-founded when it contains no 1916:. In other words, a relation is well founded if: 1405: 2209:systems, a Noetherian relation is also called 2118:is a well-founded relation. If the order is a 5182: 3424: 3324:Theory of Relations, Volume 145 - 1st Edition 3043:"B" > "AB" > "AAB" > "AAAB" > ... 2031:Some authors include an extra condition that 1670:in the "Antisymmetric" column, respectively. 62: 8: 3356:Elements of mathematics. Commutative algebra 2678:That is, if we want to construct a function 2624: 2114:is called well-founded if the corresponding 5840:Positive cone of a partially ordered group 5189: 5175: 5167: 4250: 3845: 3613: 3431: 3417: 3409: 3128:that is extensional, there exists a class 2416: 2412: 2396: 2392: 2377: 2355: 2161:, asserts that all sets are well-founded. 1958: 1954: 1941: 69: 55: 38: 3081:, then the descending chains starting at 2643: 2639: 2627: 2589: 2457: 2433: 2384: 2335: 2024:{\displaystyle (\forall S\subseteq X)\;.} 2004: 1921: 1792: 1766: 1740: 1705: 1681: 1609: 1589: 1587: 1557: 1555: 1528: 1503: 1486: 1484: 1459: 1442: 1440: 1415: 1401: 1399: 1363: 1340: 1330: 1328: 1301: 1272: 1259: 1257: 1224: 1203: 1201: 1171: 1145: 5823:Positive cone of an ordered vector space 3366:Just, Winfried and Weese, Martin (1998) 3262: 2823:. See those articles for more details. 2749:is the graph of the successor function 1951: 1179: 52: 3327:(1st ed.). Elsevier. p. 46. 3219:. More generally, when working with a 3014:if and only if there is an edge from 2800:is well-founded is also known as the 7: 3273:Introduction to axiomatic set theory 2776:. If we consider the order relation 1673:All definitions tacitly require the 1188:{\displaystyle S\neq \varnothing :} 5350:Properties & Types ( 2570:. Then there is a unique function 2516:a function that assigns an object 2442: 2362: 2340: 1995: 1980: 1962: 1926: 25: 5806:Positive cone of an ordered field 5660:Ordered topological vector space 5150: 3368:Discovering Modern Set Theory. I 3321:Fraisse, R. (15 December 2000). 3271:Zaring W.M., G. Takeuti (1971). 2246:is some property of elements of 2157:, which is one of the axioms of 2145:relation is well-founded on the 1658: 1645: 1574:{\displaystyle {\text{not }}aRa} 1079: 1069: 1039: 1029: 1007: 997: 962: 940: 930: 895: 863: 853: 828: 796: 781: 761: 729: 719: 709: 689: 657: 637: 627: 617: 585: 565: 521: 501: 491: 454: 429: 419: 387: 362: 325: 295: 263: 201: 166: 3073:is a well-founded relation and 2438: 2432: 2600: 2594: 2467: 2461: 2454: 2439: 2429: 2426: 2420: 2413: 2409: 2406: 2400: 2393: 2378: 2374: 2359: 2356: 2352: 2337: 2235:) is a well-founded relation, 2015: 2012: 1998: 1992: 1977: 1974: 1959: 1955: 1942: 1938: 1923: 1666:in the "Symmetric" column and 1602: 1347: 1292: 1221: 1: 5617:Series-parallel partial order 5111:History of mathematical logic 3372:American Mathematical Society 3041:) order, since the sequence 1667: 1654: 1064: 1059: 1054: 1049: 1024: 992: 987: 982: 977: 972: 957: 925: 920: 915: 910: 905: 890: 878: 873: 848: 843: 838: 823: 811: 806: 791: 776: 771: 756: 744: 739: 704: 699: 684: 672: 667: 652: 647: 612: 600: 595: 580: 575: 560: 555: 550: 536: 531: 516: 511: 486: 481: 469: 464: 449: 444: 439: 414: 402: 397: 382: 377: 372: 357: 352: 340: 335: 320: 315: 310: 305: 290: 278: 273: 258: 253: 248: 243: 238: 233: 216: 211: 196: 191: 186: 181: 176: 5296:Cantor's isomorphism theorem 5036:Primitive recursive function 2842:, with the order defined by 2201:is also said to satisfy the 32:Noetherian topological space 5336:Szpilrajn extension theorem 5311:Hausdorff maximal principle 5286:Boolean prime ideal theorem 2531:to each pair of an element 2250:, and we want to show that 2159:Zermelo–Fraenkel set theory 2042:Equivalently, assuming the 1884:; that is, there exists an 5889: 5682:Topological vector lattice 4100:Schröder–Bernstein theorem 3827:Monadic predicate calculus 3486:Foundations of mathematics 3393:Introduction to Set Theory 2811:, the technique is called 2790:course-of-values recursion 2512:well-founded relation and 2276:it suffices to show that: 2048:infinite descending chains 29: 5204: 5146: 5133:Philosophy of mathematics 5082:Automated theorem proving 4253: 4207:Von Neumann–Bernays–Gödel 3848: 2895:is a proper substring of 2225:can be used on them: if ( 2203:ascending chain condition 2099:for every natural number 2044:axiom of dependent choice 5291:Cantor–Bernstein theorem 3118:Mostowski collapse lemma 3048:The set of non-negative 2994:The nodes of any finite 5835:Partially ordered group 5655:Specialization preorder 4783:Self-verifying theories 4604:Tarski's axiomatization 3555:Tarski's undefinability 3550:incompleteness theorems 3269:See Definition 6.21 in 2802:well-ordering principle 2264:holds for all elements 2217:Induction and recursion 27:Type of binary relation 5321:Kruskal's tree theorem 5316:Knaster–Tarski theorem 5306:Dushnik–Miller theorem 5157:Mathematics portal 4768:Proof of impossibility 4416:propositional variable 3726:Propositional calculus 3030:The negative integers 2996:directed acyclic graph 2877:The set of all finite 2766:mathematical induction 2670: 2477: 2025: 1853:or, more generally, a 1810: 1781: 1755: 1729: 1728:{\displaystyle a,b,c,} 1690: 1631: 1575: 1543: 1516: 1472: 1428: 1387: 1316: 1245: 1189: 1160: 5026:Kolmogorov complexity 4979:Computably enumerable 4879:Model complete theory 4671:Principia Mathematica 3731:Propositional formula 3560:Banach–Tarski paradox 2813:transfinite induction 2792:. The statement that 2671: 2494:transfinite recursion 2478: 2223:transfinite induction 2170:converse well-founded 2026: 1894:such that, for every 1811: 1782: 1756: 1730: 1691: 1632: 1576: 1544: 1517: 1473: 1429: 1388: 1317: 1246: 1190: 1161: 1140:Definitions, for all 5813:Ordered vector space 4974:Church–Turing thesis 4961:Computability theory 4170:continuum hypothesis 3688:Square of opposition 3546:Gödel's completeness 3354:Bourbaki, N. (1972) 2998:, with the relation 2817:structural induction 2760:. Then induction on 2697:using the values of 2588: 2574:such that for every 2334: 2205:. In the context of 2174:upwards well-founded 2122:then it is called a 1920: 1904:, one does not have 1809:{\displaystyle aRc.} 1791: 1765: 1739: 1704: 1680: 1675:homogeneous relation 1586: 1554: 1527: 1483: 1439: 1398: 1327: 1256: 1200: 1170: 1144: 886:Strict partial order 161:Equivalence relation 5651:Alexandrov topology 5597:Lexicographic order 5556:Well-quasi-ordering 5128:Mathematical object 5019:P versus NP problem 4984:Computable function 4778:Reverse mathematics 4704:Logical consequence 4581:primitive recursive 4576:elementary function 4349:Free/bound variable 4202:Tarski–Grothendieck 3721:Logical connectives 3651:Logical equivalence 3501:Logical consequence 2989:axiom of regularity 2774:primitive recursion 2768:, and recursion on 2193:is well-founded on 2155:axiom of regularity 1780:{\displaystyle bRc} 1754:{\displaystyle aRb} 1542:{\displaystyle aRa} 1159:{\displaystyle a,b} 545:Well-quasi-ordering 5632:Transitive closure 5592:Converse/Transpose 5301:Dilworth's theorem 4926:Transfer principle 4889:Semantics of logic 4874:Categorical theory 4850:Non-standard model 4364:Logical connective 3491:Information theory 3440:Mathematical logic 3002:defined such that 2786:complete induction 2741:is the set of all 2666: 2473: 2326:must also be true. 2147:transitive closure 2021: 1806: 1777: 1751: 1725: 1686: 1627: 1625: 1571: 1539: 1512: 1510: 1468: 1466: 1424: 1422: 1383: 1381: 1312: 1310: 1241: 1239: 1185: 1156: 1020:Strict total order 5860: 5859: 5818:Partially ordered 5627:Symmetric closure 5612:Reflexive closure 5355: 5164: 5163: 5096:Abstract category 4899:Theories of truth 4709:Rule of inference 4699:Natural deduction 4680: 4679: 4225: 4224: 3930:Cartesian product 3835: 3834: 3741:Many-valued logic 3716:Boolean functions 3599:Russell's paradox 3574:diagonal argument 3471:First-order logic 3358:, Addison-Wesley. 3144:is isomorphic to 3077:is an element of 3032:{−1, −2, −3, ...} 2436: 2284:is an element of 2186:converse relation 1822: 1821: 1689:{\displaystyle R} 1640: 1639: 1612: 1560: 1506: 1462: 1418: 1366: 1275: 953:Strict weak order 139:Total, Semiconnex 16:(Redirected from 5880: 5602:Linear extension 5351: 5331:Mirsky's theorem 5191: 5184: 5177: 5168: 5155: 5154: 5106:History of logic 5101:Category of sets 4994:Decision problem 4773:Ordinal analysis 4714:Sequent calculus 4612:Boolean algebras 4552: 4551: 4526: 4497:logical/constant 4251: 4237: 4160:Zermelo–Fraenkel 3911:Set operations: 3846: 3783: 3614: 3594:Löwenheim–Skolem 3481:Formal semantics 3433: 3426: 3419: 3410: 3359: 3352: 3346: 3345: 3343: 3341: 3318: 3312: 3311: 3309: 3307: 3293: 3287: 3286: 3267: 3252: 3242: 3232: 3218: 3208: 3198: 3188: 3183: 3180:holds for every 3179: 3163: 3151: 3143: 3131: 3127: 3123: 3112: 3108: 3104: 3092: 3088: 3084: 3080: 3076: 3072: 3061:Other properties 3050:rational numbers 3044: 3033: 3021: 3017: 3013: 3001: 2983: 2967: 2951: 2911: 2898: 2894: 2890: 2873: 2863: 2857: 2851: 2841: 2799: 2783: 2771: 2763: 2759: 2748: 2740: 2734: 2719: 2707: 2696: 2686:, we may define 2685: 2681: 2675: 2673: 2672: 2667: 2662: 2658: 2657: 2656: 2655: 2651: 2647: 2583: 2573: 2569: 2565: 2544: 2540: 2530: 2515: 2507: 2482: 2480: 2479: 2474: 2437: 2434: 2388: 2325: 2314: 2302: 2299:is true for all 2298: 2287: 2283: 2271: 2267: 2263: 2249: 2245: 2234: 2200: 2196: 2192: 2183: 2167: 2152: 2139:well-founded set 2136: 2102: 2098: 2077: 2073: 2034: 2030: 2028: 2027: 2022: 2008: 1915: 1903: 1893: 1883: 1880:with respect to 1875: 1859: 1836: 1815: 1813: 1812: 1807: 1786: 1784: 1783: 1778: 1760: 1758: 1757: 1752: 1734: 1732: 1731: 1726: 1695: 1693: 1692: 1687: 1669: 1665: 1662: 1661: 1656: 1652: 1649: 1648: 1636: 1634: 1633: 1628: 1626: 1613: 1610: 1580: 1578: 1577: 1572: 1561: 1558: 1548: 1546: 1545: 1540: 1521: 1519: 1518: 1513: 1511: 1507: 1504: 1477: 1475: 1474: 1469: 1467: 1463: 1460: 1433: 1431: 1430: 1425: 1423: 1419: 1416: 1392: 1390: 1389: 1384: 1382: 1367: 1364: 1341: 1321: 1319: 1318: 1313: 1311: 1302: 1276: 1273: 1250: 1248: 1247: 1242: 1240: 1225: 1206: 1194: 1192: 1191: 1186: 1165: 1163: 1162: 1157: 1086: 1083: 1082: 1076: 1073: 1072: 1066: 1061: 1056: 1051: 1046: 1043: 1042: 1036: 1033: 1032: 1026: 1014: 1011: 1010: 1004: 1001: 1000: 994: 989: 984: 979: 974: 969: 966: 965: 959: 947: 944: 943: 937: 934: 933: 927: 922: 917: 912: 907: 902: 899: 898: 892: 880: 875: 870: 867: 866: 860: 857: 856: 850: 845: 840: 835: 832: 831: 825: 819:Meet-semilattice 813: 808: 803: 800: 799: 793: 788: 785: 784: 778: 773: 768: 765: 764: 758: 752:Join-semilattice 746: 741: 736: 733: 732: 726: 723: 722: 716: 713: 712: 706: 701: 696: 693: 692: 686: 674: 669: 664: 661: 660: 654: 649: 644: 641: 640: 634: 631: 630: 624: 621: 620: 614: 602: 597: 592: 589: 588: 582: 577: 572: 569: 568: 562: 557: 552: 547: 538: 533: 528: 525: 524: 518: 513: 508: 505: 504: 498: 495: 494: 488: 483: 471: 466: 461: 458: 457: 451: 446: 441: 436: 433: 432: 426: 423: 422: 416: 404: 399: 394: 391: 390: 384: 379: 374: 369: 366: 365: 359: 354: 342: 337: 332: 329: 328: 322: 317: 312: 307: 302: 299: 298: 292: 280: 275: 270: 267: 266: 260: 255: 250: 245: 240: 235: 230: 228: 218: 213: 208: 205: 204: 198: 193: 188: 183: 178: 173: 170: 169: 163: 81: 80: 71: 64: 57: 50: 48:binary relations 39: 21: 5888: 5887: 5883: 5882: 5881: 5879: 5878: 5877: 5873:Wellfoundedness 5863: 5862: 5861: 5856: 5852:Young's lattice 5708: 5636: 5575: 5425:Heyting algebra 5373:Boolean algebra 5345: 5326:Laver's theorem 5274: 5240:Boolean algebra 5235:Binary relation 5223: 5200: 5195: 5165: 5160: 5149: 5142: 5087:Category theory 5077:Algebraic logic 5060: 5031:Lambda calculus 4969:Church encoding 4955: 4931:Truth predicate 4787: 4753:Complete theory 4676: 4545: 4541: 4537: 4532: 4524: 4244: and  4240: 4235: 4221: 4197:New Foundations 4165:axiom of choice 4148: 4110:Gödel numbering 4050: and  4042: 3946: 3831: 3781: 3762: 3711:Boolean algebra 3697: 3661:Equiconsistency 3626:Classical logic 3603: 3584:Halting problem 3572: and  3548: and  3536: and  3535: 3530:Theorems ( 3525: 3442: 3437: 3363: 3362: 3353: 3349: 3339: 3337: 3335: 3320: 3319: 3315: 3305: 3303: 3295: 3294: 3290: 3283: 3270: 3268: 3264: 3259: 3244: 3234: 3233:if and only if 3224: 3210: 3200: 3199:if and only if 3190: 3187:1 ≄ 1 ≄ 1 ≄ ... 3186: 3181: 3169: 3161: 3158: 3145: 3133: 3129: 3125: 3121: 3110: 3106: 3094: 3090: 3086: 3082: 3078: 3074: 3066: 3063: 3042: 3031: 3019: 3015: 3003: 2999: 2982: 2975: 2969: 2966: 2959: 2953: 2952:if and only if 2949: 2942: 2935: 2928: 2921: 2918:natural numbers 2903: 2896: 2892: 2891:if and only if 2882: 2865: 2861: 2855: 2843: 2839: 2829: 2809:ordinal numbers 2793: 2777: 2769: 2761: 2750: 2746: 2743:natural numbers 2736: 2724: 2709: 2698: 2687: 2683: 2679: 2632: 2628: 2623: 2613: 2609: 2586: 2585: 2575: 2571: 2567: 2549: 2547:initial segment 2542: 2541:and a function 2532: 2517: 2513: 2497: 2332: 2331: 2316: 2304: 2300: 2289: 2285: 2281: 2269: 2265: 2254: 2247: 2236: 2226: 2219: 2198: 2197:. In this case 2194: 2188: 2181: 2165: 2150: 2134: 2100: 2097: 2088: 2079: 2075: 2074:of elements of 2071: 2064: 2057: 2051: 2032: 1918: 1917: 1905: 1895: 1885: 1881: 1878:minimal element 1867: 1857: 1834: 1832:binary relation 1824: 1823: 1816: 1789: 1788: 1763: 1762: 1737: 1736: 1702: 1701: 1678: 1677: 1671: 1663: 1659: 1650: 1646: 1624: 1623: 1606: 1605: 1584: 1583: 1552: 1551: 1525: 1524: 1509: 1508: 1500: 1499: 1481: 1480: 1465: 1464: 1456: 1455: 1437: 1436: 1421: 1420: 1412: 1411: 1396: 1395: 1380: 1379: 1368: 1351: 1350: 1342: 1325: 1324: 1309: 1308: 1303: 1289: 1288: 1277: 1274: and  1254: 1253: 1238: 1237: 1226: 1218: 1217: 1198: 1197: 1168: 1167: 1142: 1141: 1084: 1080: 1074: 1070: 1044: 1040: 1034: 1030: 1012: 1008: 1002: 998: 967: 963: 945: 941: 935: 931: 900: 896: 868: 864: 858: 854: 833: 829: 801: 797: 786: 782: 766: 762: 734: 730: 724: 720: 714: 710: 694: 690: 662: 658: 642: 638: 632: 628: 622: 618: 590: 586: 570: 566: 543: 526: 522: 506: 502: 496: 492: 477:Prewellordering 459: 455: 434: 430: 424: 420: 392: 388: 367: 363: 330: 326: 300: 296: 268: 264: 226: 223: 206: 202: 171: 167: 159: 151: 75: 42: 35: 28: 23: 22: 15: 12: 11: 5: 5886: 5884: 5876: 5875: 5865: 5864: 5858: 5857: 5855: 5854: 5849: 5844: 5843: 5842: 5832: 5831: 5830: 5825: 5820: 5810: 5809: 5808: 5798: 5793: 5792: 5791: 5786: 5779:Order morphism 5776: 5775: 5774: 5764: 5759: 5754: 5749: 5744: 5743: 5742: 5732: 5727: 5722: 5716: 5714: 5710: 5709: 5707: 5706: 5705: 5704: 5699: 5697:Locally convex 5694: 5689: 5679: 5677:Order topology 5674: 5673: 5672: 5670:Order topology 5667: 5657: 5647: 5645: 5638: 5637: 5635: 5634: 5629: 5624: 5619: 5614: 5609: 5604: 5599: 5594: 5589: 5583: 5581: 5577: 5576: 5574: 5573: 5563: 5553: 5548: 5543: 5538: 5533: 5528: 5523: 5518: 5517: 5516: 5506: 5501: 5500: 5499: 5494: 5489: 5484: 5482:Chain-complete 5474: 5469: 5468: 5467: 5462: 5457: 5452: 5447: 5437: 5432: 5427: 5422: 5417: 5407: 5402: 5397: 5392: 5387: 5382: 5381: 5380: 5370: 5365: 5359: 5357: 5347: 5346: 5344: 5343: 5338: 5333: 5328: 5323: 5318: 5313: 5308: 5303: 5298: 5293: 5288: 5282: 5280: 5276: 5275: 5273: 5272: 5267: 5262: 5257: 5252: 5247: 5242: 5237: 5231: 5229: 5225: 5224: 5222: 5221: 5216: 5211: 5205: 5202: 5201: 5196: 5194: 5193: 5186: 5179: 5171: 5162: 5161: 5147: 5144: 5143: 5141: 5140: 5135: 5130: 5125: 5120: 5119: 5118: 5108: 5103: 5098: 5089: 5084: 5079: 5074: 5072:Abstract logic 5068: 5066: 5062: 5061: 5059: 5058: 5053: 5051:Turing machine 5048: 5043: 5038: 5033: 5028: 5023: 5022: 5021: 5016: 5011: 5006: 5001: 4991: 4989:Computable set 4986: 4981: 4976: 4971: 4965: 4963: 4957: 4956: 4954: 4953: 4948: 4943: 4938: 4933: 4928: 4923: 4918: 4917: 4916: 4911: 4906: 4896: 4891: 4886: 4884:Satisfiability 4881: 4876: 4871: 4870: 4869: 4859: 4858: 4857: 4847: 4846: 4845: 4840: 4835: 4830: 4825: 4815: 4814: 4813: 4808: 4801:Interpretation 4797: 4795: 4789: 4788: 4786: 4785: 4780: 4775: 4770: 4765: 4755: 4750: 4749: 4748: 4747: 4746: 4736: 4731: 4721: 4716: 4711: 4706: 4701: 4696: 4690: 4688: 4682: 4681: 4678: 4677: 4675: 4674: 4666: 4665: 4664: 4663: 4658: 4657: 4656: 4651: 4646: 4626: 4625: 4624: 4622:minimal axioms 4619: 4608: 4607: 4606: 4595: 4594: 4593: 4588: 4583: 4578: 4573: 4568: 4555: 4553: 4534: 4533: 4531: 4530: 4529: 4528: 4516: 4511: 4510: 4509: 4504: 4499: 4494: 4484: 4479: 4474: 4469: 4468: 4467: 4462: 4452: 4451: 4450: 4445: 4440: 4435: 4425: 4420: 4419: 4418: 4413: 4408: 4398: 4397: 4396: 4391: 4386: 4381: 4376: 4371: 4361: 4356: 4351: 4346: 4345: 4344: 4339: 4334: 4329: 4319: 4314: 4312:Formation rule 4309: 4304: 4303: 4302: 4297: 4287: 4286: 4285: 4275: 4270: 4265: 4260: 4254: 4248: 4231:Formal systems 4227: 4226: 4223: 4222: 4220: 4219: 4214: 4209: 4204: 4199: 4194: 4189: 4184: 4179: 4174: 4173: 4172: 4167: 4156: 4154: 4150: 4149: 4147: 4146: 4145: 4144: 4134: 4129: 4128: 4127: 4120:Large cardinal 4117: 4112: 4107: 4102: 4097: 4083: 4082: 4081: 4076: 4071: 4056: 4054: 4044: 4043: 4041: 4040: 4039: 4038: 4033: 4028: 4018: 4013: 4008: 4003: 3998: 3993: 3988: 3983: 3978: 3973: 3968: 3963: 3957: 3955: 3948: 3947: 3945: 3944: 3943: 3942: 3937: 3932: 3927: 3922: 3917: 3909: 3908: 3907: 3902: 3892: 3887: 3885:Extensionality 3882: 3880:Ordinal number 3877: 3867: 3862: 3861: 3860: 3849: 3843: 3837: 3836: 3833: 3832: 3830: 3829: 3824: 3819: 3814: 3809: 3804: 3799: 3798: 3797: 3787: 3786: 3785: 3772: 3770: 3764: 3763: 3761: 3760: 3759: 3758: 3753: 3748: 3738: 3733: 3728: 3723: 3718: 3713: 3707: 3705: 3699: 3698: 3696: 3695: 3690: 3685: 3680: 3675: 3670: 3665: 3664: 3663: 3653: 3648: 3643: 3638: 3633: 3628: 3622: 3620: 3611: 3605: 3604: 3602: 3601: 3596: 3591: 3586: 3581: 3576: 3564:Cantor's  3562: 3557: 3552: 3542: 3540: 3527: 3526: 3524: 3523: 3518: 3513: 3508: 3503: 3498: 3493: 3488: 3483: 3478: 3473: 3468: 3463: 3462: 3461: 3450: 3448: 3444: 3443: 3438: 3436: 3435: 3428: 3421: 3413: 3407: 3406: 3382: 3361: 3360: 3347: 3333: 3313: 3288: 3281: 3261: 3260: 3258: 3255: 3164:is said to be 3157: 3154: 3103:− 2, ..., 2, 1 3062: 3059: 3058: 3057: 3046: 3035: 3024: 3023: 2992: 2985: 2980: 2973: 2964: 2957: 2947: 2940: 2933: 2926: 2900: 2875: 2853:if and only if 2840:{1, 2, 3, ...} 2828: 2825: 2665: 2661: 2654: 2650: 2646: 2642: 2638: 2635: 2631: 2626: 2622: 2619: 2616: 2612: 2608: 2605: 2602: 2599: 2596: 2593: 2472: 2469: 2466: 2463: 2460: 2456: 2453: 2450: 2447: 2444: 2441: 2431: 2428: 2425: 2422: 2419: 2415: 2411: 2408: 2405: 2402: 2399: 2395: 2391: 2387: 2383: 2380: 2376: 2373: 2370: 2367: 2364: 2361: 2358: 2354: 2351: 2348: 2345: 2342: 2339: 2328: 2327: 2274: 2273: 2218: 2215: 2143:set membership 2095: 2083: 2069: 2062: 2055: 2020: 2017: 2014: 2011: 2007: 2003: 2000: 1997: 1994: 1991: 1988: 1985: 1982: 1979: 1976: 1973: 1970: 1967: 1964: 1961: 1957: 1953: 1950: 1947: 1944: 1940: 1937: 1934: 1931: 1928: 1925: 1820: 1819: 1805: 1802: 1799: 1796: 1776: 1773: 1770: 1750: 1747: 1744: 1724: 1721: 1718: 1715: 1712: 1709: 1685: 1642: 1641: 1638: 1637: 1622: 1619: 1616: 1608: 1607: 1604: 1601: 1598: 1595: 1592: 1591: 1581: 1570: 1567: 1564: 1549: 1538: 1535: 1532: 1522: 1502: 1501: 1498: 1495: 1492: 1489: 1488: 1478: 1458: 1457: 1454: 1451: 1448: 1445: 1444: 1434: 1414: 1413: 1410: 1407: 1404: 1403: 1393: 1378: 1375: 1372: 1369: 1365: or  1362: 1359: 1356: 1353: 1352: 1349: 1346: 1343: 1339: 1336: 1333: 1332: 1322: 1307: 1304: 1300: 1297: 1294: 1291: 1290: 1287: 1284: 1281: 1278: 1271: 1268: 1265: 1262: 1261: 1251: 1236: 1233: 1230: 1227: 1223: 1220: 1219: 1216: 1213: 1210: 1207: 1205: 1195: 1184: 1181: 1178: 1175: 1155: 1152: 1149: 1137: 1136: 1131: 1126: 1121: 1116: 1111: 1106: 1101: 1096: 1091: 1088: 1087: 1077: 1067: 1062: 1057: 1052: 1047: 1037: 1027: 1022: 1016: 1015: 1005: 995: 990: 985: 980: 975: 970: 960: 955: 949: 948: 938: 928: 923: 918: 913: 908: 903: 893: 888: 882: 881: 876: 871: 861: 851: 846: 841: 836: 826: 821: 815: 814: 809: 804: 794: 789: 779: 774: 769: 759: 754: 748: 747: 742: 737: 727: 717: 707: 702: 697: 687: 682: 676: 675: 670: 665: 655: 650: 645: 635: 625: 615: 610: 604: 603: 598: 593: 583: 578: 573: 563: 558: 553: 548: 540: 539: 534: 529: 519: 514: 509: 499: 489: 484: 479: 473: 472: 467: 462: 452: 447: 442: 437: 427: 417: 412: 406: 405: 400: 395: 385: 380: 375: 370: 360: 355: 350: 348:Total preorder 344: 343: 338: 333: 323: 318: 313: 308: 303: 293: 288: 282: 281: 276: 271: 261: 256: 251: 246: 241: 236: 231: 220: 219: 214: 209: 199: 194: 189: 184: 179: 174: 164: 156: 155: 153: 148: 146: 144: 142: 140: 137: 135: 133: 130: 129: 124: 119: 114: 109: 104: 99: 94: 89: 84: 77: 76: 74: 73: 66: 59: 51: 37: 36: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 5885: 5874: 5871: 5870: 5868: 5853: 5850: 5848: 5845: 5841: 5838: 5837: 5836: 5833: 5829: 5826: 5824: 5821: 5819: 5816: 5815: 5814: 5811: 5807: 5804: 5803: 5802: 5801:Ordered field 5799: 5797: 5794: 5790: 5787: 5785: 5782: 5781: 5780: 5777: 5773: 5770: 5769: 5768: 5765: 5763: 5760: 5758: 5757:Hasse diagram 5755: 5753: 5750: 5748: 5745: 5741: 5738: 5737: 5736: 5735:Comparability 5733: 5731: 5728: 5726: 5723: 5721: 5718: 5717: 5715: 5711: 5703: 5700: 5698: 5695: 5693: 5690: 5688: 5685: 5684: 5683: 5680: 5678: 5675: 5671: 5668: 5666: 5663: 5662: 5661: 5658: 5656: 5652: 5649: 5648: 5646: 5643: 5639: 5633: 5630: 5628: 5625: 5623: 5620: 5618: 5615: 5613: 5610: 5608: 5607:Product order 5605: 5603: 5600: 5598: 5595: 5593: 5590: 5588: 5585: 5584: 5582: 5580:Constructions 5578: 5572: 5568: 5564: 5561: 5557: 5554: 5552: 5549: 5547: 5544: 5542: 5539: 5537: 5534: 5532: 5529: 5527: 5524: 5522: 5519: 5515: 5512: 5511: 5510: 5507: 5505: 5502: 5498: 5495: 5493: 5490: 5488: 5485: 5483: 5480: 5479: 5478: 5477:Partial order 5475: 5473: 5470: 5466: 5465:Join and meet 5463: 5461: 5458: 5456: 5453: 5451: 5448: 5446: 5443: 5442: 5441: 5438: 5436: 5433: 5431: 5428: 5426: 5423: 5421: 5418: 5416: 5412: 5408: 5406: 5403: 5401: 5398: 5396: 5393: 5391: 5388: 5386: 5383: 5379: 5376: 5375: 5374: 5371: 5369: 5366: 5364: 5363:Antisymmetric 5361: 5360: 5358: 5354: 5348: 5342: 5339: 5337: 5334: 5332: 5329: 5327: 5324: 5322: 5319: 5317: 5314: 5312: 5309: 5307: 5304: 5302: 5299: 5297: 5294: 5292: 5289: 5287: 5284: 5283: 5281: 5277: 5271: 5270:Weak ordering 5268: 5266: 5263: 5261: 5258: 5256: 5255:Partial order 5253: 5251: 5248: 5246: 5243: 5241: 5238: 5236: 5233: 5232: 5230: 5226: 5220: 5217: 5215: 5212: 5210: 5207: 5206: 5203: 5199: 5192: 5187: 5185: 5180: 5178: 5173: 5172: 5169: 5159: 5158: 5153: 5145: 5139: 5136: 5134: 5131: 5129: 5126: 5124: 5121: 5117: 5114: 5113: 5112: 5109: 5107: 5104: 5102: 5099: 5097: 5093: 5090: 5088: 5085: 5083: 5080: 5078: 5075: 5073: 5070: 5069: 5067: 5063: 5057: 5054: 5052: 5049: 5047: 5046:Recursive set 5044: 5042: 5039: 5037: 5034: 5032: 5029: 5027: 5024: 5020: 5017: 5015: 5012: 5010: 5007: 5005: 5002: 5000: 4997: 4996: 4995: 4992: 4990: 4987: 4985: 4982: 4980: 4977: 4975: 4972: 4970: 4967: 4966: 4964: 4962: 4958: 4952: 4949: 4947: 4944: 4942: 4939: 4937: 4934: 4932: 4929: 4927: 4924: 4922: 4919: 4915: 4912: 4910: 4907: 4905: 4902: 4901: 4900: 4897: 4895: 4892: 4890: 4887: 4885: 4882: 4880: 4877: 4875: 4872: 4868: 4865: 4864: 4863: 4860: 4856: 4855:of arithmetic 4853: 4852: 4851: 4848: 4844: 4841: 4839: 4836: 4834: 4831: 4829: 4826: 4824: 4821: 4820: 4819: 4816: 4812: 4809: 4807: 4804: 4803: 4802: 4799: 4798: 4796: 4794: 4790: 4784: 4781: 4779: 4776: 4774: 4771: 4769: 4766: 4763: 4762:from ZFC 4759: 4756: 4754: 4751: 4745: 4742: 4741: 4740: 4737: 4735: 4732: 4730: 4727: 4726: 4725: 4722: 4720: 4717: 4715: 4712: 4710: 4707: 4705: 4702: 4700: 4697: 4695: 4692: 4691: 4689: 4687: 4683: 4673: 4672: 4668: 4667: 4662: 4661:non-Euclidean 4659: 4655: 4652: 4650: 4647: 4645: 4644: 4640: 4639: 4637: 4634: 4633: 4631: 4627: 4623: 4620: 4618: 4615: 4614: 4613: 4609: 4605: 4602: 4601: 4600: 4596: 4592: 4589: 4587: 4584: 4582: 4579: 4577: 4574: 4572: 4569: 4567: 4564: 4563: 4561: 4557: 4556: 4554: 4549: 4543: 4538:Example  4535: 4527: 4522: 4521: 4520: 4517: 4515: 4512: 4508: 4505: 4503: 4500: 4498: 4495: 4493: 4490: 4489: 4488: 4485: 4483: 4480: 4478: 4475: 4473: 4470: 4466: 4463: 4461: 4458: 4457: 4456: 4453: 4449: 4446: 4444: 4441: 4439: 4436: 4434: 4431: 4430: 4429: 4426: 4424: 4421: 4417: 4414: 4412: 4409: 4407: 4404: 4403: 4402: 4399: 4395: 4392: 4390: 4387: 4385: 4382: 4380: 4377: 4375: 4372: 4370: 4367: 4366: 4365: 4362: 4360: 4357: 4355: 4352: 4350: 4347: 4343: 4340: 4338: 4335: 4333: 4330: 4328: 4325: 4324: 4323: 4320: 4318: 4315: 4313: 4310: 4308: 4305: 4301: 4298: 4296: 4295:by definition 4293: 4292: 4291: 4288: 4284: 4281: 4280: 4279: 4276: 4274: 4271: 4269: 4266: 4264: 4261: 4259: 4256: 4255: 4252: 4249: 4247: 4243: 4238: 4232: 4228: 4218: 4215: 4213: 4210: 4208: 4205: 4203: 4200: 4198: 4195: 4193: 4190: 4188: 4185: 4183: 4182:Kripke–Platek 4180: 4178: 4175: 4171: 4168: 4166: 4163: 4162: 4161: 4158: 4157: 4155: 4151: 4143: 4140: 4139: 4138: 4135: 4133: 4130: 4126: 4123: 4122: 4121: 4118: 4116: 4113: 4111: 4108: 4106: 4103: 4101: 4098: 4095: 4091: 4087: 4084: 4080: 4077: 4075: 4072: 4070: 4067: 4066: 4065: 4061: 4058: 4057: 4055: 4053: 4049: 4045: 4037: 4034: 4032: 4029: 4027: 4026:constructible 4024: 4023: 4022: 4019: 4017: 4014: 4012: 4009: 4007: 4004: 4002: 3999: 3997: 3994: 3992: 3989: 3987: 3984: 3982: 3979: 3977: 3974: 3972: 3969: 3967: 3964: 3962: 3959: 3958: 3956: 3954: 3949: 3941: 3938: 3936: 3933: 3931: 3928: 3926: 3923: 3921: 3918: 3916: 3913: 3912: 3910: 3906: 3903: 3901: 3898: 3897: 3896: 3893: 3891: 3888: 3886: 3883: 3881: 3878: 3876: 3872: 3868: 3866: 3863: 3859: 3856: 3855: 3854: 3851: 3850: 3847: 3844: 3842: 3838: 3828: 3825: 3823: 3820: 3818: 3815: 3813: 3810: 3808: 3805: 3803: 3800: 3796: 3793: 3792: 3791: 3788: 3784: 3779: 3778: 3777: 3774: 3773: 3771: 3769: 3765: 3757: 3754: 3752: 3749: 3747: 3744: 3743: 3742: 3739: 3737: 3734: 3732: 3729: 3727: 3724: 3722: 3719: 3717: 3714: 3712: 3709: 3708: 3706: 3704: 3703:Propositional 3700: 3694: 3691: 3689: 3686: 3684: 3681: 3679: 3676: 3674: 3671: 3669: 3666: 3662: 3659: 3658: 3657: 3654: 3652: 3649: 3647: 3644: 3642: 3639: 3637: 3634: 3632: 3631:Logical truth 3629: 3627: 3624: 3623: 3621: 3619: 3615: 3612: 3610: 3606: 3600: 3597: 3595: 3592: 3590: 3587: 3585: 3582: 3580: 3577: 3575: 3571: 3567: 3563: 3561: 3558: 3556: 3553: 3551: 3547: 3544: 3543: 3541: 3539: 3533: 3528: 3522: 3519: 3517: 3514: 3512: 3509: 3507: 3504: 3502: 3499: 3497: 3494: 3492: 3489: 3487: 3484: 3482: 3479: 3477: 3474: 3472: 3469: 3467: 3464: 3460: 3457: 3456: 3455: 3452: 3451: 3449: 3445: 3441: 3434: 3429: 3427: 3422: 3420: 3415: 3414: 3411: 3405: 3404:0-8247-7915-0 3401: 3398: 3397:Marcel Dekker 3394: 3390: 3386: 3385:Karel Hrbáček 3383: 3380: 3379:0-8218-0266-6 3376: 3373: 3369: 3365: 3364: 3357: 3351: 3348: 3336: 3334:9780444505422 3330: 3326: 3325: 3317: 3314: 3302: 3298: 3292: 3289: 3284: 3278: 3274: 3266: 3263: 3256: 3254: 3251: 3247: 3241: 3237: 3231: 3227: 3222: 3217: 3213: 3207: 3203: 3197: 3193: 3178: 3175: 3172: 3167: 3155: 3153: 3149: 3141: 3137: 3119: 3114: 3102: 3098: 3070: 3060: 3055: 3051: 3047: 3040: 3039:lexicographic 3036: 3029: 3028: 3027: 3012: 3009: 3006: 2997: 2993: 2990: 2986: 2979: 2972: 2963: 2956: 2946: 2939: 2932: 2925: 2920:, ordered by 2919: 2915: 2910: 2906: 2901: 2889: 2885: 2880: 2876: 2872: 2868: 2860: 2854: 2850: 2846: 2838: 2835:The positive 2834: 2833: 2832: 2826: 2824: 2822: 2818: 2814: 2810: 2805: 2803: 2797: 2791: 2787: 2781: 2775: 2767: 2764:is the usual 2757: 2753: 2744: 2739: 2732: 2728: 2721: 2718: 2715: 2712: 2705: 2701: 2694: 2690: 2676: 2663: 2659: 2652: 2648: 2644: 2640: 2636: 2633: 2629: 2620: 2617: 2614: 2610: 2606: 2603: 2597: 2591: 2582: 2578: 2563: 2560: 2557: 2553: 2548: 2539: 2535: 2528: 2524: 2520: 2511: 2505: 2501: 2495: 2490: 2488: 2483: 2470: 2464: 2458: 2451: 2448: 2445: 2423: 2417: 2403: 2397: 2389: 2385: 2381: 2371: 2368: 2365: 2349: 2346: 2343: 2323: 2319: 2313: 2310: 2307: 2296: 2292: 2279: 2278: 2277: 2261: 2257: 2253: 2252: 2251: 2243: 2239: 2233: 2229: 2224: 2216: 2214: 2212: 2208: 2204: 2191: 2187: 2179: 2175: 2171: 2162: 2160: 2156: 2148: 2144: 2140: 2132: 2127: 2125: 2121: 2117: 2113: 2112:partial order 2109: 2104: 2094: 2091: 2086: 2082: 2068: 2061: 2054: 2049: 2045: 2040: 2038: 2018: 2009: 2005: 2001: 1989: 1986: 1983: 1971: 1968: 1965: 1948: 1945: 1935: 1932: 1929: 1914: 1911: 1908: 1902: 1898: 1892: 1888: 1879: 1874: 1870: 1866: 1863: 1856: 1852: 1848: 1844: 1840: 1833: 1829: 1818: 1803: 1800: 1797: 1794: 1774: 1771: 1768: 1748: 1745: 1742: 1722: 1719: 1716: 1713: 1710: 1707: 1699: 1683: 1676: 1644: 1643: 1620: 1617: 1614: 1599: 1596: 1593: 1582: 1568: 1565: 1562: 1550: 1536: 1533: 1530: 1523: 1496: 1493: 1490: 1479: 1452: 1449: 1446: 1435: 1408: 1394: 1376: 1373: 1370: 1360: 1357: 1354: 1344: 1337: 1334: 1323: 1305: 1298: 1295: 1285: 1282: 1279: 1269: 1266: 1263: 1252: 1234: 1231: 1228: 1214: 1211: 1208: 1196: 1182: 1176: 1173: 1153: 1150: 1147: 1139: 1138: 1135: 1132: 1130: 1127: 1125: 1122: 1120: 1117: 1115: 1112: 1110: 1107: 1105: 1102: 1100: 1099:Antisymmetric 1097: 1095: 1092: 1090: 1089: 1078: 1068: 1063: 1058: 1053: 1048: 1038: 1028: 1023: 1021: 1018: 1017: 1006: 996: 991: 986: 981: 976: 971: 961: 956: 954: 951: 950: 939: 929: 924: 919: 914: 909: 904: 894: 889: 887: 884: 883: 877: 872: 862: 852: 847: 842: 837: 827: 822: 820: 817: 816: 810: 805: 795: 790: 780: 775: 770: 760: 755: 753: 750: 749: 743: 738: 728: 718: 708: 703: 698: 688: 683: 681: 678: 677: 671: 666: 656: 651: 646: 636: 626: 616: 611: 609: 608:Well-ordering 606: 605: 599: 594: 584: 579: 574: 564: 559: 554: 549: 546: 542: 541: 535: 530: 520: 515: 510: 500: 490: 485: 480: 478: 475: 474: 468: 463: 453: 448: 443: 438: 428: 418: 413: 411: 408: 407: 401: 396: 386: 381: 376: 371: 361: 356: 351: 349: 346: 345: 339: 334: 324: 319: 314: 309: 304: 294: 289: 287: 286:Partial order 284: 283: 277: 272: 262: 257: 252: 247: 242: 237: 232: 229: 222: 221: 215: 210: 200: 195: 190: 185: 180: 175: 165: 162: 158: 157: 154: 149: 147: 145: 143: 141: 138: 136: 134: 132: 131: 128: 125: 123: 120: 118: 115: 113: 110: 108: 105: 103: 100: 98: 95: 93: 92:Antisymmetric 90: 88: 85: 83: 82: 79: 78: 72: 67: 65: 60: 58: 53: 49: 45: 41: 40: 33: 19: 5644:& Orders 5622:Star product 5551:Well-founded 5550: 5504:Prefix order 5460:Distributive 5450:Complemented 5420:Foundational 5385:Completeness 5341:Zorn's lemma 5245:Cyclic order 5228:Key concepts 5198:Order theory 5148: 4946:Ultraproduct 4793:Model theory 4758:Independence 4694:Formal proof 4686:Proof theory 4669: 4642: 4599:real numbers 4571:second-order 4482:Substitution 4359:Metalanguage 4300:conservative 4273:Axiom schema 4217:Constructive 4187:Morse–Kelley 4153:Set theories 4132:Aleph number 4125:inaccessible 4031:Grothendieck 3915:intersection 3802:Higher-order 3790:Second-order 3736:Truth tables 3693:Venn diagram 3476:Formal proof 3392: 3367: 3355: 3350: 3338:. Retrieved 3323: 3316: 3304:. Retrieved 3300: 3291: 3272: 3265: 3249: 3245: 3239: 3235: 3229: 3225: 3215: 3211: 3205: 3201: 3195: 3191: 3176: 3173: 3170: 3159: 3147: 3139: 3135: 3115: 3100: 3096: 3068: 3064: 3025: 3010: 3007: 3004: 2977: 2970: 2961: 2954: 2944: 2937: 2930: 2923: 2908: 2904: 2887: 2883: 2870: 2866: 2848: 2844: 2830: 2806: 2795: 2784:, we obtain 2779: 2755: 2751: 2737: 2730: 2726: 2722: 2716: 2713: 2710: 2703: 2699: 2692: 2688: 2677: 2580: 2576: 2561: 2558: 2555: 2551: 2537: 2533: 2526: 2522: 2518: 2503: 2499: 2491: 2487:Emmy Noether 2484: 2329: 2321: 2317: 2311: 2308: 2305: 2294: 2290: 2275: 2259: 2255: 2241: 2237: 2231: 2227: 2220: 2210: 2189: 2177: 2173: 2169: 2163: 2138: 2137:is called a 2128: 2116:strict order 2108:order theory 2105: 2092: 2089: 2084: 2080: 2066: 2059: 2052: 2041: 1912: 1909: 1906: 1900: 1896: 1890: 1886: 1872: 1868: 1847:foundational 1846: 1842: 1839:well-founded 1838: 1825: 1672: 1109:Well-founded 1108: 227:(Quasiorder) 102:Well-founded 101: 18:Well-founded 5828:Riesz space 5789:Isomorphism 5665:Normal cone 5587:Composition 5521:Semilattice 5430:Homogeneous 5415:Equivalence 5265:Total order 5056:Type theory 5004:undecidable 4936:Truth value 4823:equivalence 4502:non-logical 4115:Enumeration 4105:Isomorphism 4052:cardinality 4036:Von Neumann 4001:Ultrafilter 3966:Uncountable 3900:equivalence 3817:Quantifiers 3807:Fixed-point 3776:First-order 3656:Consistency 3641:Proposition 3618:Traditional 3589:Lindström's 3579:Compactness 3521:Type theory 3466:Cardinality 3389:Thomas Jech 3340:20 February 3160:A relation 3156:Reflexivity 3124:on a class 3105:has length 2821:∈-induction 2211:terminating 2164:A relation 2120:total order 1843:wellfounded 1828:mathematics 1129:Irreflexive 410:Total order 122:Irreflexive 5796:Order type 5730:Cofinality 5571:Well-order 5546:Transitive 5435:Idempotent 5368:Asymmetric 4867:elementary 4560:arithmetic 4428:Quantifier 4406:functional 4278:Expression 3996:Transitive 3940:identities 3925:complement 3858:hereditary 3841:Set theory 3282:0387900241 3257:References 3132:such that 2303:such that 2178:Noetherian 2131:set theory 2124:well-order 2078:such that 1837:is called 1700:: for all 1698:transitive 1134:Asymmetric 127:Asymmetric 44:Transitive 5847:Upper set 5784:Embedding 5720:Antichain 5541:Tolerance 5531:Symmetric 5526:Semiorder 5472:Reflexive 5390:Connected 5138:Supertask 5041:Recursion 4999:decidable 4833:saturated 4811:of models 4734:deductive 4729:axiomatic 4649:Hilbert's 4636:Euclidean 4617:canonical 4540:axiomatic 4472:Signature 4401:Predicate 4290:Extension 4212:Ackermann 4137:Operation 4016:Universal 4006:Recursive 3981:Singleton 3976:Inhabited 3961:Countable 3951:Types of 3935:power set 3905:partition 3822:Predicate 3768:Predicate 3683:Syllogism 3673:Soundness 3646:Inference 3636:Tautology 3538:paradoxes 3301:ProofWiki 3166:reflexive 2449:∈ 2443:∀ 2414:⟹ 2394:⟹ 2369:∈ 2363:∀ 2347:∈ 2341:∀ 2330:That is, 2207:rewriting 2184:, if the 1996:¬ 1987:∈ 1981:∀ 1969:∈ 1963:∃ 1956:⟹ 1952:∅ 1949:≠ 1933:⊆ 1927:∀ 1862:non-empty 1860:if every 1611:not  1603:⇒ 1559:not  1494:∧ 1450:∨ 1348:⇒ 1338:≠ 1293:⇒ 1222:⇒ 1180:∅ 1177:≠ 1124:Reflexive 1119:Has meets 1114:Has joins 1104:Connected 1094:Symmetric 225:Preorder 152:reflexive 117:Reflexive 112:Has meets 107:Has joins 97:Connected 87:Symmetric 5867:Category 5642:Topology 5509:Preorder 5492:Eulerian 5455:Complete 5405:Directed 5395:Covering 5260:Preorder 5219:Category 5214:Glossary 5123:Logicism 5116:timeline 5092:Concrete 4951:Validity 4921:T-schema 4914:Kripke's 4909:Tarski's 4904:semantic 4894:Strength 4843:submodel 4838:spectrum 4806:function 4654:Tarski's 4643:Elements 4630:geometry 4586:Robinson 4507:variable 4492:function 4465:spectrum 4455:Sentence 4411:variable 4354:Language 4307:Relation 4268:Automata 4258:Alphabet 4242:language 4096:-jection 4074:codomain 4060:Function 4021:Universe 3991:Infinite 3895:Relation 3678:Validity 3668:Argument 3566:theorem, 3221:preorder 3109:for any 2936:) < ( 2902:The set 2837:integers 2827:Examples 2735:, where 2510:set-like 2133:, a set 2037:set-like 1668:✗ 1655:✗ 1065:✗ 1060:✗ 1055:✗ 1050:✗ 1025:✗ 993:✗ 988:✗ 983:✗ 978:✗ 973:✗ 958:✗ 926:✗ 921:✗ 916:✗ 911:✗ 906:✗ 891:✗ 879:✗ 874:✗ 849:✗ 844:✗ 839:✗ 824:✗ 812:✗ 807:✗ 792:✗ 777:✗ 772:✗ 757:✗ 745:✗ 740:✗ 705:✗ 700:✗ 685:✗ 673:✗ 668:✗ 653:✗ 648:✗ 613:✗ 601:✗ 596:✗ 581:✗ 576:✗ 561:✗ 556:✗ 551:✗ 537:✗ 532:✗ 517:✗ 512:✗ 487:✗ 482:✗ 470:✗ 465:✗ 450:✗ 445:✗ 440:✗ 415:✗ 403:✗ 398:✗ 383:✗ 378:✗ 373:✗ 358:✗ 353:✗ 341:✗ 336:✗ 321:✗ 316:✗ 311:✗ 306:✗ 291:✗ 279:✗ 274:✗ 259:✗ 254:✗ 249:✗ 244:✗ 239:✗ 234:✗ 217:✗ 212:✗ 197:✗ 192:✗ 187:✗ 182:✗ 177:✗ 5747:Duality 5725:Cofinal 5713:Related 5692:FrĂ©chet 5569:)  5445:Bounded 5440:Lattice 5413:)  5411:Partial 5279:Results 5250:Lattice 5065:Related 4862:Diagram 4760: ( 4739:Hilbert 4724:Systems 4719:Theorem 4597:of the 4542:systems 4322:Formula 4317:Grammar 4233: ( 4177:General 3890:Forcing 3875:Element 3795:Monadic 3570:paradox 3511:Theorem 3447:General 3391:(1999) 3071:, <) 2879:strings 2859:divides 2798:, <) 2782:, <) 2545:on the 2435:implies 2315:, then 2141:if the 1849:) on a 680:Lattice 5772:Subnet 5752:Filter 5702:Normed 5687:Banach 5653:& 5560:Better 5497:Strict 5487:Graded 5378:topics 5209:Topics 4828:finite 4591:Skolem 4544:  4519:Theory 4487:Symbol 4477:String 4460:atomic 4337:ground 4332:closed 4327:atomic 4283:ground 4246:syntax 4142:binary 4069:domain 3986:Finite 3751:finite 3609:Logics 3568:  3516:Theory 3402:  3387:& 3377:  3331:  3306:10 May 3279:  2788:, and 2772:gives 2745:, and 2496:. Let 2153:. The 1876:has a 1865:subset 1505:exists 1461:exists 1417:exists 46:  5762:Ideal 5740:Graph 5536:Total 5514:Total 5400:Dense 4818:Model 4566:Peano 4423:Proof 4263:Arity 4192:Naive 4079:image 4011:Fuzzy 3971:Empty 3920:union 3865:Class 3506:Model 3496:Lemma 3454:Axiom 3228:< 3194:< 3099:− 1, 3054:reals 2976:< 2960:< 2914:pairs 2886:< 2847:< 2508:be a 2072:, ... 1855:class 1787:then 150:Anti- 5353:list 4941:Type 4744:list 4548:list 4525:list 4514:Term 4448:rank 4342:open 4236:list 4048:Maps 3953:sets 3812:Free 3782:list 3532:list 3459:list 3400:ISBN 3375:ISBN 3342:2019 3329:ISBN 3308:2021 3277:ISBN 3243:and 3209:and 3150:, ∈) 3116:The 3052:(or 2968:and 2864:and 2708:for 2288:and 2110:, a 1841:(or 1830:, a 1761:and 1166:and 5767:Net 5567:Pre 4628:of 4610:of 4558:of 4090:Sur 4064:Map 3871:Ur- 3853:Set 3248:≰ 3168:if 3095:ω, 3065:If 3018:to 2916:of 2912:of 2682:on 2566:of 2280:If 2268:of 2180:on 2176:or 2168:is 2149:of 2129:In 2106:In 2035:is 1851:set 1845:or 1826:In 1735:if 1696:be 1406:min 5869:: 5014:NP 4638:: 4632:: 4562:: 4239:), 4094:Bi 4086:In 3370:, 3299:. 3238:≀ 3214:≠ 3204:≀ 3152:. 3138:, 3113:. 2943:, 2929:, 2907:× 2869:≠ 2804:. 2758:+1 2754:↩ 2729:, 2720:. 2584:, 2579:∈ 2554:: 2536:∈ 2525:, 2502:, 2489:. 2230:, 2213:. 2172:, 2126:. 2103:. 2087:+1 2065:, 2058:, 1899:∈ 1889:∈ 1871:⊆ 5565:( 5562:) 5558:( 5409:( 5356:) 5190:e 5183:t 5176:v 5094:/ 5009:P 4764:) 4550:) 4546:( 4443:∀ 4438:! 4433:∃ 4394:= 4389:↔ 4384:→ 4379:∧ 4374:√ 4369:ÂŹ 4092:/ 4088:/ 4062:/ 3873:) 3869:( 3756:∞ 3746:3 3534:) 3432:e 3425:t 3418:v 3381:. 3344:. 3310:. 3285:. 3250:a 3246:b 3240:b 3236:a 3230:b 3226:a 3216:b 3212:a 3206:b 3202:a 3196:b 3192:a 3182:a 3177:a 3174:R 3171:a 3162:R 3148:C 3146:( 3142:) 3140:R 3136:X 3134:( 3130:C 3126:X 3122:R 3111:n 3107:n 3101:n 3097:n 3091:X 3087:X 3083:x 3079:X 3075:x 3069:X 3067:( 3022:. 3020:b 3016:a 3011:b 3008:R 3005:a 3000:R 2991:. 2984:. 2981:2 2978:m 2974:2 2971:n 2965:1 2962:m 2958:1 2955:n 2950:) 2948:2 2945:m 2941:1 2938:m 2934:2 2931:n 2927:1 2924:n 2922:( 2909:N 2905:N 2899:. 2897:t 2893:s 2888:t 2884:s 2874:. 2871:b 2867:a 2862:b 2856:a 2849:b 2845:a 2796:N 2794:( 2780:N 2778:( 2770:S 2762:S 2756:x 2752:x 2747:S 2738:N 2733:) 2731:S 2727:N 2725:( 2717:x 2714:R 2711:y 2706:) 2704:y 2702:( 2700:G 2695:) 2693:x 2691:( 2689:G 2684:X 2680:G 2664:. 2660:) 2653:} 2649:x 2645:R 2641:y 2637:: 2634:y 2630:{ 2625:| 2621:G 2618:, 2615:x 2611:( 2607:F 2604:= 2601:) 2598:x 2595:( 2592:G 2581:X 2577:x 2572:G 2568:X 2564:} 2562:x 2559:R 2556:y 2552:y 2550:{ 2543:g 2538:X 2534:x 2529:) 2527:g 2523:x 2521:( 2519:F 2514:F 2506:) 2504:R 2500:X 2498:( 2471:. 2468:) 2465:x 2462:( 2459:P 2455:) 2452:X 2446:x 2440:( 2430:] 2427:) 2424:x 2421:( 2418:P 2410:] 2407:) 2404:y 2401:( 2398:P 2390:x 2386:R 2382:y 2379:[ 2375:) 2372:X 2366:y 2360:( 2357:[ 2353:) 2350:X 2344:x 2338:( 2324:) 2322:x 2320:( 2318:P 2312:x 2309:R 2306:y 2301:y 2297:) 2295:y 2293:( 2291:P 2286:X 2282:x 2272:, 2270:X 2266:x 2262:) 2260:x 2258:( 2256:P 2248:X 2244:) 2242:x 2240:( 2238:P 2232:R 2228:X 2199:R 2195:X 2190:R 2182:X 2166:R 2151:x 2135:x 2101:n 2096:n 2093:x 2090:R 2085:n 2081:x 2076:X 2070:2 2067:x 2063:1 2060:x 2056:0 2053:x 2033:R 2019:. 2016:] 2013:) 2010:m 2006:R 2002:s 1999:( 1993:) 1990:S 1984:s 1978:( 1975:) 1972:S 1966:m 1960:( 1946:S 1943:[ 1939:) 1936:X 1930:S 1924:( 1913:m 1910:R 1907:s 1901:S 1897:s 1891:S 1887:m 1882:R 1873:X 1869:S 1858:X 1835:R 1804:. 1801:c 1798:R 1795:a 1775:c 1772:R 1769:b 1749:b 1746:R 1743:a 1723:, 1720:c 1717:, 1714:b 1711:, 1708:a 1684:R 1664:Y 1651:Y 1621:a 1618:R 1615:b 1600:b 1597:R 1594:a 1569:a 1566:R 1563:a 1537:a 1534:R 1531:a 1497:b 1491:a 1453:b 1447:a 1409:S 1377:a 1374:R 1371:b 1361:b 1358:R 1355:a 1345:b 1335:a 1306:b 1299:= 1296:a 1286:a 1283:R 1280:b 1270:b 1267:R 1264:a 1235:a 1232:R 1229:b 1215:b 1212:R 1209:a 1183:: 1174:S 1154:b 1151:, 1148:a 1085:Y 1075:Y 1045:Y 1035:Y 1013:Y 1003:Y 968:Y 946:Y 936:Y 901:Y 869:Y 859:Y 834:Y 802:Y 787:Y 767:Y 735:Y 725:Y 715:Y 695:Y 663:Y 643:Y 633:Y 623:Y 591:Y 571:Y 527:Y 507:Y 497:Y 460:Y 435:Y 425:Y 393:Y 368:Y 331:Y 301:Y 269:Y 207:Y 172:Y 70:e 63:t 56:v 34:. 20:)

Index

Well-founded
Noetherian topological space
Transitive
binary relations
v
t
e
Symmetric
Antisymmetric
Connected
Well-founded
Has joins
Has meets
Reflexive
Irreflexive
Asymmetric
Equivalence relation
Preorder (Quasiorder)
Partial order
Total preorder
Total order
Prewellordering
Well-quasi-ordering
Well-ordering
Lattice
Join-semilattice
Meet-semilattice
Strict partial order
Strict weak order
Strict total order

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