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Cofinal (mathematics)

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1067:, a subset is cofinal if and only if it contains that greatest element (this follows, since a greatest element is necessarily a maximal element). Partially ordered sets without greatest element or maximal elements admit disjoint cofinal subsets. For example, the even and odd 1863: 1763: 2269: 1348: 2309: 2031: 1900: 2419: 2138: 2601: 2567: 2478: 2378: 2198: 2097: 1930: 1394: 1583: 1489: 1813: 1722: 1548: 2882: 2732: 2626: 2507: 2444: 1959: 2781: 2529: 2344: 2160: 1678: 1207: 746: 426: 68: 2063: 3136: 1700: 1426: 1302: 1259: 1177: 583: 456: 373: 103: 846: 634: 544: 3214: 2685: 1985: 1652: 1522: 791: 489: 266: 160: 3188: 3162: 2853: 2827: 817: 515: 670: 3055: 2755: 2708: 1626: 1143: 1047: 924: 713: 400: 344: 3104: 3032: 3012: 2992: 2960: 2928: 2904: 2801: 2653: 1789: 1603: 1454: 1227: 1116: 1092: 1024: 1004: 984: 964: 944: 901: 690: 317: 240: 220: 200: 180: 131: 4006: 3989: 3519: 1818: 1727: 3355: 3316: 3287: 3836: 2207: 3972: 3831: 3826: 3462: 1307: 3544: 2276: 1998: 860: 3863: 3783: 1868: 3648: 3577: 3457: 2387: 2106: 2572: 2538: 2449: 2349: 2169: 2068: 3551: 3539: 3502: 3477: 3452: 3406: 3375: 1905: 1353: 376: 17: 1557: 1463: 3848: 3482: 3472: 3348: 3821: 3487: 1794: 1705: 1531: 3753: 3380: 2858: 2713: 2606: 2487: 2424: 1935: 1063:
any element of the subset, violating the definition of cofinal. For a partially ordered set with a
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to the notion of cofinal subset. Cofinal (respectively coinitial) subsets are precisely the
767: 757: 465: 245: 136: 3167: 3141: 2832: 2806: 796: 494: 3979: 3938: 3928: 3918: 3663: 3626: 3616: 3596: 3581: 280: 3297: 646: 8: 3906: 3817: 3763: 3722: 3712: 3601: 3534: 3497: 2935: 2907: 1492: 880: 641: 3037: 2737: 2690: 1608: 1125: 1029: 906: 695: 382: 326: 4018: 3945: 3798: 3707: 3697: 3638: 3556: 3492: 3089: 3017: 2997: 2977: 2945: 2913: 2889: 2786: 2638: 1774: 1588: 1439: 1212: 1101: 1077: 1009: 989: 969: 949: 929: 886: 876: 675: 302: 225: 205: 185: 165: 116: 3858: 3955: 3933: 3793: 3778: 3758: 3561: 3322: 3312: 3283: 1767: 1457: 276: 3768: 3621: 3293: 1064: 292: 3950: 3733: 3611: 3606: 3591: 3507: 3416: 3401: 2939: 2931: 1095: 1056: 1052: 3868: 3853: 3843: 3702: 3680: 3658: 3304: 2967: 2163: 1068: 590: 71: 4033: 3967: 3923: 3901: 3773: 3643: 3631: 3436: 3326: 2963: 1551: 1396:
is cofinal. This property is not true in general without the hypothesis that
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is a directed set and if some union of (one or more) finitely many subsets
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is sufficient to construct and describe the profinite completion of
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form disjoint cofinal subsets of the set of all natural numbers.
2532: 3333: 3083: â€“ Subset of a preorder that contains all larger elements 42: 3241: 3239: 3237: 3235: 3233: 3231: 3228: 1858:{\displaystyle \left({\mathcal {N}}_{x},\supseteq \right);} 1758:{\displaystyle {\mathcal {B}}\subseteq {\mathcal {N}}_{x}} 2166:(consisting of positive integers) is a cofinal subset of 3070:
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3068: â€“ Being a subset whose complement is a finite set 3196: 3170: 3144: 3112: 3092: 3040: 3020: 3000: 2980: 2948: 2916: 2892: 2861: 2835: 2809: 2789: 2763: 2740: 2716: 2693: 2664: 2641: 2609: 2575: 2541: 2515: 2490: 2452: 2427: 2390: 2352: 2317: 2279: 2210: 2172: 2146: 2109: 2071: 2039: 2001: 1967: 1938: 1908: 1871: 1821: 1797: 1777: 1730: 1708: 1686: 1660: 1634: 1611: 1591: 1560: 1534: 1501: 1466: 1442: 1402: 1356: 1310: 1278: 1269:
Any superset of a cofinal subset is itself cofinal.
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Cofinal subsets are very important in the theory of
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The cofinal relation over partially ordered sets ("
3282:(Third ed.), Reading, Mass.: Addison-Wesley, 3208: 3182: 3156: 3130: 3098: 3049: 3026: 3006: 2986: 2954: 2922: 2898: 2876: 2847: 2821: 2795: 2775: 2749: 2726: 2702: 2679: 2647: 2620: 2595: 2561: 2523: 2501: 2472: 2438: 2413: 2372: 2338: 2303: 2263: 2192: 2154: 2132: 2091: 2057: 2025: 1979: 1953: 1924: 1894: 1857: 1807: 1783: 1757: 1716: 1694: 1672: 1646: 1620: 1597: 1577: 1542: 1516: 1483: 1448: 1420: 1388: 1342: 1296: 1253: 1221: 1201: 1171: 1137: 1110: 1086: 1041: 1018: 998: 978: 958: 938: 918: 895: 840: 811: 785: 740: 707: 684: 664: 628: 577: 538: 509: 483: 450: 420: 394: 367: 338: 311: 260: 234: 214: 194: 174: 154: 125: 97: 62: 553:. This definition is most commonly applied when 4031: 34:Mathematical property of subsets in order theory 3014:). In this situation, every cofinal subset of 879:: every poset is cofinal in itself. It is also 859:with respect to the right (respectively left) 3349: 2635:A particular but important case is given if 2446:of negative integers is a cofinal subset of 2255: 2222: 760:) if it satisfies the following condition: 1343:{\displaystyle S_{1}\cup \cdots \cup S_{n}} 4007:Positive cone of a partially ordered group 3356: 3342: 1098:cofinal subset, then we can find a subset 458:if it satisfies the following condition: 3303: 3245: 2717: 2630: 2611: 2580: 2546: 2517: 2492: 2457: 2432: 2395: 2357: 2304:{\displaystyle -\infty <y<\infty ,} 2215: 2177: 2148: 2114: 2076: 2026:{\displaystyle -\infty <x<\infty ,} 1713: 1709: 1691: 1687: 1539: 1535: 447: 443: 364: 360: 3990:Positive cone of an ordered vector space 3309:Handbook of Analysis and Its Foundations 1350:is cofinal then at least one of the set 1055:, every cofinal subset must contain all 636:between two directed sets is said to be 549:A subset that is not frequent is called 283:” is the appropriate generalization of " 3251: 3077: â€“ Size of subsets in order theory 1895:{\displaystyle N\in {\mathcal {N}}_{x}} 1432:Subset relations and neighborhood bases 14: 4032: 3257: 3337: 2414:{\displaystyle (\mathbb {R} ,\leq ).} 2204:true of the set of negative integers 2133:{\displaystyle (\mathbb {R} ,\geq ).} 3274: 2596:{\displaystyle (\mathbb {R} ,\geq )} 2562:{\displaystyle (\mathbb {R} ,\leq )} 2473:{\displaystyle (\mathbb {R} ,\geq )} 2373:{\displaystyle (\mathbb {R} ,\geq )} 2193:{\displaystyle (\mathbb {R} ,\leq )} 2092:{\displaystyle (\mathbb {R} ,\leq )} 2994:(which are parametrized by the set 1991:Cofinal subsets of the real numbers 1925:{\displaystyle B\in {\mathcal {B}}} 1389:{\displaystyle S_{1},\ldots ,S_{n}} 24: 3517:Properties & Types ( 2665: 2324: 2295: 2283: 2049: 2017: 2005: 1917: 1881: 1865:that is, if and only if for every 1830: 1800: 1744: 1733: 1578:{\displaystyle {\mathcal {N}}_{x}} 1564: 1484:{\displaystyle {\mathcal {N}}_{x}} 1470: 1265:Examples and sufficient conditions 162:it is possible to find an element 25: 4051: 3973:Positive cone of an ordered field 3311:. San Diego, CA: Academic Press. 1051:For a partially ordered set with 3827:Ordered topological vector space 3363: 903:is a cofinal subset of a poset 287:". They are also important in 3125: 3113: 2674: 2668: 2603:; the same is true of the set 2590: 2576: 2556: 2542: 2467: 2453: 2405: 2391: 2367: 2353: 2333: 2318: 2187: 2173: 2124: 2110: 2086: 2072: 2052: 2040: 1808:{\displaystyle {\mathcal {B}}} 1717:{\displaystyle \,\supseteq \,} 1543:{\displaystyle \,\supseteq \,} 1415: 1403: 1291: 1279: 1248: 1236: 1166: 1154: 966:(with the partial ordering of 659: 653: 620: 572: 560: 348: 92: 80: 13: 1: 3784:Series-parallel partial order 3221: 2877:{\displaystyle a\supseteq b.} 2727:{\displaystyle \,\supseteq .} 2710:ordered by reverse inclusion 2621:{\displaystyle \mathbb {Q} .} 2569:and also a cofinal subset of 2502:{\displaystyle \mathbb {N} .} 2439:{\displaystyle -\mathbb {N} } 1954:{\displaystyle N\supseteq B.} 866: 593:with additional properties. 295:, where the minimum possible 3463:Cantor's isomorphism theorem 3138:that contains every element 2776:{\displaystyle B\subseteq A} 2524:{\displaystyle \mathbb {Z} } 2484:true of the natural numbers 2339:{\displaystyle (-\infty ,y)} 2155:{\displaystyle \mathbb {N} } 1673:{\displaystyle S\supseteq T} 1202:{\displaystyle B\subseteq A} 1026:is also a cofinal subset of 741:{\displaystyle B\subseteq A} 421:{\displaystyle B\subseteq A} 222:" (explicitly, "larger than 63:{\displaystyle B\subseteq A} 7: 3503:Szpilrajn extension theorem 3478:Hausdorff maximal principle 3453:Boolean prime ideal theorem 3106:of a partially ordered set 3059: 2058:{\displaystyle (x,\infty )} 1585:: explicitly, for any sets 1074:If a partially ordered set 377:homogeneous binary relation 10: 4056: 3849:Topological vector lattice 291:, including the theory of 26: 3879: 3807: 3746: 3516: 3445: 3394: 3371: 3131:{\displaystyle (P,\leq )} 1695:{\displaystyle \,\leq \,} 1421:{\displaystyle (A,\leq )} 1297:{\displaystyle (A,\leq )} 1261:is also a directed set. 1254:{\displaystyle (B,\leq )} 1172:{\displaystyle (A,\leq )} 578:{\displaystyle (A,\leq )} 451:{\displaystyle \,\leq \,} 368:{\displaystyle \,\leq \,} 98:{\displaystyle (A,\leq )} 3458:Cantor–Bernstein theorem 841:{\displaystyle b\leq a.} 629:{\displaystyle f:X\to A} 539:{\displaystyle a\leq b.} 27:Not to be confused with 4002:Partially ordered group 3822:Specialization preorder 3265:. Springer. p. 16. 3209:{\displaystyle x\leq y} 2734:Given this ordering of 2680:{\displaystyle \wp (E)} 2535:is a cofinal subset of 2346:is a cofinal subset of 2065:is a cofinal subset of 1980:{\displaystyle N\leq B} 1815:is a cofinal subset of 1647:{\displaystyle S\leq T} 1517:{\displaystyle x\in X.} 1209:is a cofinal subset of 946:is a cofinal subset of 786:{\displaystyle a\in A,} 692:is a cofinal subset of 484:{\displaystyle a\in A,} 299:of a cofinal subset of 261:{\displaystyle a\leq b} 155:{\displaystyle a\in A,} 3488:Kruskal's tree theorem 3483:Knaster–Tarski theorem 3473:Dushnik–Miller theorem 3210: 3184: 3183:{\displaystyle x\in U} 3164:for which there is an 3158: 3157:{\displaystyle y\in P} 3132: 3100: 3051: 3028: 3008: 2988: 2956: 2924: 2900: 2878: 2849: 2848:{\displaystyle b\in B} 2823: 2822:{\displaystyle a\in A} 2797: 2777: 2751: 2728: 2704: 2681: 2649: 2631:Cofinal set of subsets 2622: 2597: 2563: 2525: 2503: 2474: 2440: 2415: 2374: 2340: 2305: 2265: 2194: 2156: 2134: 2093: 2059: 2027: 1981: 1955: 1926: 1896: 1859: 1809: 1785: 1759: 1718: 1696: 1674: 1648: 1622: 1599: 1579: 1544: 1518: 1485: 1450: 1422: 1390: 1344: 1298: 1255: 1223: 1203: 1173: 1139: 1112: 1088: 1043: 1020: 1000: 980: 960: 940: 920: 897: 842: 813: 812:{\displaystyle b\in B} 787: 742: 709: 686: 666: 630: 579: 540: 511: 510:{\displaystyle b\in B} 485: 452: 422: 396: 369: 340: 319:is referred to as the 313: 262: 236: 216: 196: 176: 156: 127: 99: 64: 3263:Topology and Geometry 3211: 3185: 3159: 3133: 3101: 3052: 3029: 3009: 2989: 2962:is defined to be the 2957: 2925: 2901: 2879: 2850: 2824: 2798: 2778: 2752: 2729: 2705: 2682: 2650: 2623: 2598: 2564: 2526: 2504: 2475: 2441: 2416: 2375: 2341: 2306: 2266: 2195: 2157: 2135: 2094: 2060: 2028: 1982: 1956: 1927: 1897: 1860: 1810: 1786: 1760: 1719: 1697: 1675: 1649: 1623: 1600: 1580: 1545: 1519: 1486: 1451: 1423: 1391: 1345: 1299: 1256: 1224: 1204: 1174: 1140: 1113: 1089: 1061:less than or equal to 1044: 1021: 1001: 981: 961: 941: 921: 898: 843: 814: 788: 743: 710: 687: 667: 631: 580: 541: 512: 486: 453: 423: 397: 370: 341: 314: 263: 237: 217: 202:that is "larger than 197: 177: 157: 128: 100: 65: 3980:Ordered vector space 3194: 3168: 3142: 3110: 3090: 3038: 3018: 2998: 2978: 2946: 2940:profinite completion 2914: 2890: 2859: 2833: 2807: 2787: 2761: 2738: 2714: 2691: 2662: 2639: 2607: 2573: 2539: 2513: 2488: 2450: 2425: 2388: 2384:a cofinal subset of 2350: 2315: 2277: 2208: 2170: 2144: 2107: 2103:a cofinal subset of 2069: 2037: 1999: 1965: 1936: 1906: 1869: 1819: 1795: 1775: 1728: 1706: 1684: 1658: 1632: 1609: 1589: 1558: 1532: 1499: 1464: 1440: 1400: 1354: 1308: 1276: 1233: 1213: 1187: 1151: 1126: 1102: 1078: 1030: 1010: 990: 970: 950: 930: 907: 887: 853:order-theoretic dual 823: 797: 768: 726: 696: 676: 665:{\displaystyle f(X)} 647: 608: 557: 521: 495: 466: 440: 406: 383: 357: 327: 303: 246: 226: 206: 186: 166: 137: 117: 77: 48: 3818:Alexandrov topology 3764:Lexicographic order 3723:Well-quasi-ordering 3248:, pp. 158–165. 2655:is a subset of the 2273:Similarly, for any 1493:neighborhood filter 3799:Transitive closure 3759:Converse/Transpose 3468:Dilworth's theorem 3206: 3180: 3154: 3128: 3096: 3050:{\displaystyle E.} 3047: 3024: 3004: 2984: 2952: 2920: 2896: 2874: 2845: 2819: 2793: 2773: 2750:{\displaystyle A,} 2747: 2724: 2703:{\displaystyle E,} 2700: 2677: 2645: 2618: 2593: 2559: 2521: 2499: 2470: 2436: 2411: 2370: 2336: 2301: 2261: 2190: 2152: 2130: 2089: 2055: 2023: 1977: 1951: 1922: 1902:there exists some 1892: 1855: 1805: 1781: 1755: 1714: 1692: 1670: 1644: 1621:{\displaystyle T,} 1618: 1595: 1575: 1540: 1514: 1481: 1446: 1418: 1386: 1340: 1294: 1251: 1219: 1199: 1169: 1138:{\displaystyle A.} 1135: 1108: 1084: 1042:{\displaystyle A.} 1039: 1016: 996: 976: 956: 936: 919:{\displaystyle A,} 916: 893: 838: 809: 793:there exists some 783: 738: 708:{\displaystyle A.} 705: 682: 662: 626: 575: 536: 507: 491:there exists some 481: 448: 418: 395:{\displaystyle A.} 392: 365: 339:{\displaystyle A.} 336: 309: 258: 232: 212: 192: 172: 152: 123: 95: 60: 4027: 4026: 3985:Partially ordered 3794:Symmetric closure 3779:Reflexive closure 3522: 3318:978-0-12-622760-4 3289:978-0-201-55540-0 3099:{\displaystyle U} 3027:{\displaystyle A} 3007:{\displaystyle A} 2987:{\displaystyle E} 2955:{\displaystyle E} 2923:{\displaystyle A} 2899:{\displaystyle E} 2886:For example, let 2796:{\displaystyle A} 2648:{\displaystyle A} 1791:if (and only if) 1784:{\displaystyle x} 1768:neighborhood base 1598:{\displaystyle S} 1458:topological space 1449:{\displaystyle X} 1222:{\displaystyle A} 1111:{\displaystyle B} 1087:{\displaystyle A} 1019:{\displaystyle C} 999:{\displaystyle B} 979:{\displaystyle A} 959:{\displaystyle B} 939:{\displaystyle C} 896:{\displaystyle B} 718:Coinitial subsets 685:{\displaystyle f} 312:{\displaystyle A} 235:{\displaystyle a} 215:{\displaystyle a} 195:{\displaystyle B} 175:{\displaystyle b} 126:{\displaystyle A} 16:(Redirected from 4047: 3769:Linear extension 3518: 3498:Mirsky's theorem 3358: 3351: 3344: 3335: 3334: 3330: 3300: 3267: 3266: 3255: 3249: 3243: 3215: 3213: 3212: 3207: 3189: 3187: 3186: 3181: 3163: 3161: 3160: 3155: 3137: 3135: 3134: 3129: 3105: 3103: 3102: 3097: 3071: 3056: 3054: 3053: 3048: 3033: 3031: 3030: 3025: 3013: 3011: 3010: 3005: 2993: 2991: 2990: 2985: 2961: 2959: 2958: 2953: 2932:normal subgroups 2929: 2927: 2926: 2921: 2905: 2903: 2902: 2897: 2883: 2881: 2880: 2875: 2854: 2852: 2851: 2846: 2828: 2826: 2825: 2820: 2802: 2800: 2799: 2794: 2782: 2780: 2779: 2774: 2756: 2754: 2753: 2748: 2733: 2731: 2730: 2725: 2709: 2707: 2706: 2701: 2686: 2684: 2683: 2678: 2654: 2652: 2651: 2646: 2627: 2625: 2624: 2619: 2614: 2602: 2600: 2599: 2594: 2583: 2568: 2566: 2565: 2560: 2549: 2530: 2528: 2527: 2522: 2520: 2508: 2506: 2505: 2500: 2495: 2479: 2477: 2476: 2471: 2460: 2445: 2443: 2442: 2437: 2435: 2420: 2418: 2417: 2412: 2398: 2379: 2377: 2376: 2371: 2360: 2345: 2343: 2342: 2337: 2310: 2308: 2307: 2302: 2270: 2268: 2267: 2262: 2218: 2199: 2197: 2196: 2191: 2180: 2161: 2159: 2158: 2153: 2151: 2139: 2137: 2136: 2131: 2117: 2098: 2096: 2095: 2090: 2079: 2064: 2062: 2061: 2056: 2032: 2030: 2029: 2024: 1986: 1984: 1983: 1978: 1961:(I.e. such that 1960: 1958: 1957: 1952: 1931: 1929: 1928: 1923: 1921: 1920: 1901: 1899: 1898: 1893: 1891: 1890: 1885: 1884: 1864: 1862: 1861: 1856: 1851: 1847: 1840: 1839: 1834: 1833: 1814: 1812: 1811: 1806: 1804: 1803: 1790: 1788: 1787: 1782: 1764: 1762: 1761: 1756: 1754: 1753: 1748: 1747: 1737: 1736: 1723: 1721: 1720: 1715: 1701: 1699: 1698: 1693: 1680:(so in essence, 1679: 1677: 1676: 1671: 1653: 1651: 1650: 1645: 1627: 1625: 1624: 1619: 1604: 1602: 1601: 1596: 1584: 1582: 1581: 1576: 1574: 1573: 1568: 1567: 1549: 1547: 1546: 1541: 1523: 1521: 1520: 1515: 1490: 1488: 1487: 1482: 1480: 1479: 1474: 1473: 1455: 1453: 1452: 1447: 1427: 1425: 1424: 1419: 1395: 1393: 1392: 1387: 1385: 1384: 1366: 1365: 1349: 1347: 1346: 1341: 1339: 1338: 1320: 1319: 1303: 1301: 1300: 1295: 1260: 1258: 1257: 1252: 1228: 1226: 1225: 1220: 1208: 1206: 1205: 1200: 1178: 1176: 1175: 1170: 1144: 1142: 1141: 1136: 1117: 1115: 1114: 1109: 1093: 1091: 1090: 1085: 1065:greatest element 1057:maximal elements 1053:maximal elements 1048: 1046: 1045: 1040: 1025: 1023: 1022: 1017: 1005: 1003: 1002: 997: 985: 983: 982: 977: 965: 963: 962: 957: 945: 943: 942: 937: 925: 923: 922: 917: 902: 900: 899: 894: 847: 845: 844: 839: 818: 816: 815: 810: 792: 790: 789: 784: 756:in the sense of 747: 745: 744: 739: 714: 712: 711: 706: 691: 689: 688: 683: 671: 669: 668: 663: 635: 633: 632: 627: 584: 582: 581: 576: 545: 543: 542: 537: 516: 514: 513: 508: 490: 488: 487: 482: 457: 455: 454: 449: 436:with respect to 427: 425: 424: 419: 401: 399: 398: 393: 374: 372: 371: 366: 345: 343: 342: 337: 318: 316: 315: 310: 293:cardinal numbers 267: 265: 264: 259: 241: 239: 238: 233: 221: 219: 218: 213: 201: 199: 198: 193: 181: 179: 178: 173: 161: 159: 158: 153: 132: 130: 129: 124: 104: 102: 101: 96: 69: 67: 66: 61: 21: 4055: 4054: 4050: 4049: 4048: 4046: 4045: 4044: 4030: 4029: 4028: 4023: 4019:Young's lattice 3875: 3803: 3742: 3592:Heyting algebra 3540:Boolean algebra 3512: 3493:Laver's theorem 3441: 3407:Boolean algebra 3402:Binary relation 3390: 3367: 3362: 3319: 3305:Schechter, Eric 3290: 3271: 3270: 3256: 3252: 3244: 3229: 3224: 3195: 3192: 3191: 3169: 3166: 3165: 3143: 3140: 3139: 3111: 3108: 3107: 3091: 3088: 3087: 3069: 3062: 3039: 3036: 3035: 3019: 3016: 3015: 2999: 2996: 2995: 2979: 2976: 2975: 2947: 2944: 2943: 2915: 2912: 2911: 2891: 2888: 2887: 2860: 2857: 2856: 2834: 2831: 2830: 2808: 2805: 2804: 2788: 2785: 2784: 2762: 2759: 2758: 2739: 2736: 2735: 2715: 2712: 2711: 2692: 2689: 2688: 2663: 2660: 2659: 2640: 2637: 2636: 2633: 2610: 2608: 2605: 2604: 2579: 2574: 2571: 2570: 2545: 2540: 2537: 2536: 2516: 2514: 2511: 2510: 2491: 2489: 2486: 2485: 2456: 2451: 2448: 2447: 2431: 2426: 2423: 2422: 2394: 2389: 2386: 2385: 2356: 2351: 2348: 2347: 2316: 2313: 2312: 2278: 2275: 2274: 2214: 2209: 2206: 2205: 2176: 2171: 2168: 2167: 2164:natural numbers 2147: 2145: 2142: 2141: 2113: 2108: 2105: 2104: 2075: 2070: 2067: 2066: 2038: 2035: 2034: 2000: 1997: 1996: 1966: 1963: 1962: 1937: 1934: 1933: 1916: 1915: 1907: 1904: 1903: 1886: 1880: 1879: 1878: 1870: 1867: 1866: 1835: 1829: 1828: 1827: 1826: 1822: 1820: 1817: 1816: 1799: 1798: 1796: 1793: 1792: 1776: 1773: 1772: 1749: 1743: 1742: 1741: 1732: 1731: 1729: 1726: 1725: 1707: 1704: 1703: 1685: 1682: 1681: 1659: 1656: 1655: 1654:if and only if 1633: 1630: 1629: 1610: 1607: 1606: 1590: 1587: 1586: 1569: 1563: 1562: 1561: 1559: 1556: 1555: 1533: 1530: 1529: 1500: 1497: 1496: 1475: 1469: 1468: 1467: 1465: 1462: 1461: 1441: 1438: 1437: 1401: 1398: 1397: 1380: 1376: 1361: 1357: 1355: 1352: 1351: 1334: 1330: 1315: 1311: 1309: 1306: 1305: 1277: 1274: 1273: 1267: 1234: 1231: 1230: 1214: 1211: 1210: 1188: 1185: 1184: 1152: 1149: 1148: 1127: 1124: 1123: 1122:and cofinal in 1103: 1100: 1099: 1096:totally ordered 1079: 1076: 1075: 1069:natural numbers 1031: 1028: 1027: 1011: 1008: 1007: 991: 988: 987: 971: 968: 967: 951: 948: 947: 931: 928: 927: 908: 905: 904: 888: 885: 884: 869: 824: 821: 820: 798: 795: 794: 769: 766: 765: 727: 724: 723: 697: 694: 693: 677: 674: 673: 648: 645: 644: 609: 606: 605: 597:Final functions 558: 555: 554: 522: 519: 518: 496: 493: 492: 467: 464: 463: 441: 438: 437: 407: 404: 403: 384: 381: 380: 358: 355: 354: 351: 328: 325: 324: 304: 301: 300: 247: 244: 243: 227: 224: 223: 207: 204: 203: 187: 184: 183: 167: 164: 163: 138: 135: 134: 118: 115: 114: 78: 75: 74: 49: 46: 45: 35: 32: 23: 22: 15: 12: 11: 5: 4053: 4043: 4042: 4025: 4024: 4022: 4021: 4016: 4011: 4010: 4009: 3999: 3998: 3997: 3992: 3987: 3977: 3976: 3975: 3965: 3960: 3959: 3958: 3953: 3946:Order morphism 3943: 3942: 3941: 3931: 3926: 3921: 3916: 3911: 3910: 3909: 3899: 3894: 3889: 3883: 3881: 3877: 3876: 3874: 3873: 3872: 3871: 3866: 3864:Locally convex 3861: 3856: 3846: 3844:Order topology 3841: 3840: 3839: 3837:Order topology 3834: 3824: 3814: 3812: 3805: 3804: 3802: 3801: 3796: 3791: 3786: 3781: 3776: 3771: 3766: 3761: 3756: 3750: 3748: 3744: 3743: 3741: 3740: 3730: 3720: 3715: 3710: 3705: 3700: 3695: 3690: 3685: 3684: 3683: 3673: 3668: 3667: 3666: 3661: 3656: 3651: 3649:Chain-complete 3641: 3636: 3635: 3634: 3629: 3624: 3619: 3614: 3604: 3599: 3594: 3589: 3584: 3574: 3569: 3564: 3559: 3554: 3549: 3548: 3547: 3537: 3532: 3526: 3524: 3514: 3513: 3511: 3510: 3505: 3500: 3495: 3490: 3485: 3480: 3475: 3470: 3465: 3460: 3455: 3449: 3447: 3443: 3442: 3440: 3439: 3434: 3429: 3424: 3419: 3414: 3409: 3404: 3398: 3396: 3392: 3391: 3389: 3388: 3383: 3378: 3372: 3369: 3368: 3361: 3360: 3353: 3346: 3338: 3332: 3331: 3317: 3301: 3288: 3269: 3268: 3250: 3246:Schechter 1996 3226: 3225: 3223: 3220: 3219: 3218: 3217: 3216: 3205: 3202: 3199: 3179: 3176: 3173: 3153: 3150: 3147: 3127: 3124: 3121: 3118: 3115: 3095: 3078: 3072: 3061: 3058: 3046: 3043: 3023: 3003: 2983: 2968:inverse system 2951: 2930:be the set of 2919: 2895: 2873: 2870: 2867: 2864: 2844: 2841: 2838: 2818: 2815: 2812: 2792: 2783:is cofinal in 2772: 2769: 2766: 2746: 2743: 2723: 2720: 2699: 2696: 2676: 2673: 2670: 2667: 2644: 2632: 2629: 2617: 2613: 2592: 2589: 2586: 2582: 2578: 2558: 2555: 2552: 2548: 2544: 2519: 2498: 2494: 2483: 2469: 2466: 2463: 2459: 2455: 2434: 2430: 2410: 2407: 2404: 2401: 2397: 2393: 2383: 2369: 2366: 2363: 2359: 2355: 2335: 2332: 2329: 2326: 2323: 2320: 2300: 2297: 2294: 2291: 2288: 2285: 2282: 2260: 2257: 2254: 2251: 2248: 2245: 2242: 2239: 2236: 2233: 2230: 2227: 2224: 2221: 2217: 2213: 2203: 2189: 2186: 2183: 2179: 2175: 2150: 2129: 2126: 2123: 2120: 2116: 2112: 2102: 2088: 2085: 2082: 2078: 2074: 2054: 2051: 2048: 2045: 2042: 2022: 2019: 2016: 2013: 2010: 2007: 2004: 1993: 1992: 1976: 1973: 1970: 1950: 1947: 1944: 1941: 1919: 1914: 1911: 1889: 1883: 1877: 1874: 1854: 1850: 1846: 1843: 1838: 1832: 1825: 1802: 1780: 1770: 1752: 1746: 1740: 1735: 1712: 1690: 1669: 1666: 1663: 1643: 1640: 1637: 1617: 1614: 1594: 1572: 1566: 1538: 1513: 1510: 1507: 1504: 1478: 1472: 1445: 1434: 1433: 1417: 1414: 1411: 1408: 1405: 1383: 1379: 1375: 1372: 1369: 1364: 1360: 1337: 1333: 1329: 1326: 1323: 1318: 1314: 1293: 1290: 1287: 1284: 1281: 1266: 1263: 1250: 1247: 1244: 1241: 1238: 1218: 1198: 1195: 1192: 1168: 1165: 1162: 1159: 1156: 1134: 1131: 1107: 1083: 1062: 1038: 1035: 1015: 995: 975: 955: 935: 915: 912: 892: 868: 865: 861:order topology 849: 848: 837: 834: 831: 828: 808: 805: 802: 782: 779: 776: 773: 755: 751: 748:is said to be 737: 734: 731: 720: 719: 704: 701: 681: 661: 658: 655: 652: 639: 625: 622: 619: 616: 613: 599: 598: 591:preordered set 574: 571: 568: 565: 562: 552: 547: 546: 535: 532: 529: 526: 506: 503: 500: 480: 477: 474: 471: 446: 435: 431: 428:is said to be 417: 414: 411: 391: 388: 363: 350: 347: 335: 332: 308: 281:cofinal subnet 257: 254: 251: 231: 211: 191: 171: 151: 148: 145: 142: 122: 105:is said to be 94: 91: 88: 85: 82: 72:preordered set 59: 56: 53: 33: 9: 6: 4: 3: 2: 4052: 4041: 4038: 4037: 4035: 4020: 4017: 4015: 4012: 4008: 4005: 4004: 4003: 4000: 3996: 3993: 3991: 3988: 3986: 3983: 3982: 3981: 3978: 3974: 3971: 3970: 3969: 3968:Ordered field 3966: 3964: 3961: 3957: 3954: 3952: 3949: 3948: 3947: 3944: 3940: 3937: 3936: 3935: 3932: 3930: 3927: 3925: 3924:Hasse diagram 3922: 3920: 3917: 3915: 3912: 3908: 3905: 3904: 3903: 3902:Comparability 3900: 3898: 3895: 3893: 3890: 3888: 3885: 3884: 3882: 3878: 3870: 3867: 3865: 3862: 3860: 3857: 3855: 3852: 3851: 3850: 3847: 3845: 3842: 3838: 3835: 3833: 3830: 3829: 3828: 3825: 3823: 3819: 3816: 3815: 3813: 3810: 3806: 3800: 3797: 3795: 3792: 3790: 3787: 3785: 3782: 3780: 3777: 3775: 3774:Product order 3772: 3770: 3767: 3765: 3762: 3760: 3757: 3755: 3752: 3751: 3749: 3747:Constructions 3745: 3739: 3735: 3731: 3728: 3724: 3721: 3719: 3716: 3714: 3711: 3709: 3706: 3704: 3701: 3699: 3696: 3694: 3691: 3689: 3686: 3682: 3679: 3678: 3677: 3674: 3672: 3669: 3665: 3662: 3660: 3657: 3655: 3652: 3650: 3647: 3646: 3645: 3644:Partial order 3642: 3640: 3637: 3633: 3632:Join and meet 3630: 3628: 3625: 3623: 3620: 3618: 3615: 3613: 3610: 3609: 3608: 3605: 3603: 3600: 3598: 3595: 3593: 3590: 3588: 3585: 3583: 3579: 3575: 3573: 3570: 3568: 3565: 3563: 3560: 3558: 3555: 3553: 3550: 3546: 3543: 3542: 3541: 3538: 3536: 3533: 3531: 3530:Antisymmetric 3528: 3527: 3525: 3521: 3515: 3509: 3506: 3504: 3501: 3499: 3496: 3494: 3491: 3489: 3486: 3484: 3481: 3479: 3476: 3474: 3471: 3469: 3466: 3464: 3461: 3459: 3456: 3454: 3451: 3450: 3448: 3444: 3438: 3437:Weak ordering 3435: 3433: 3430: 3428: 3425: 3423: 3422:Partial order 3420: 3418: 3415: 3413: 3410: 3408: 3405: 3403: 3400: 3399: 3397: 3393: 3387: 3384: 3382: 3379: 3377: 3374: 3373: 3370: 3366: 3359: 3354: 3352: 3347: 3345: 3340: 3339: 3336: 3328: 3324: 3320: 3314: 3310: 3306: 3302: 3299: 3295: 3291: 3285: 3281: 3277: 3273: 3272: 3264: 3260: 3254: 3247: 3242: 3240: 3238: 3236: 3234: 3232: 3227: 3203: 3200: 3197: 3177: 3174: 3171: 3151: 3148: 3145: 3122: 3119: 3116: 3093: 3085: 3084: 3082: 3079: 3076: 3073: 3067: 3064: 3063: 3057: 3044: 3041: 3021: 3001: 2981: 2973: 2969: 2965: 2964:inverse limit 2949: 2941: 2937: 2933: 2917: 2909: 2893: 2884: 2871: 2868: 2865: 2862: 2842: 2839: 2836: 2816: 2813: 2810: 2803:if for every 2790: 2770: 2767: 2764: 2744: 2741: 2721: 2718: 2697: 2694: 2671: 2658: 2642: 2628: 2615: 2587: 2584: 2553: 2550: 2534: 2496: 2481: 2464: 2461: 2428: 2408: 2402: 2399: 2381: 2364: 2361: 2330: 2327: 2321: 2311:the interval 2298: 2292: 2289: 2286: 2280: 2271: 2258: 2252: 2249: 2246: 2243: 2240: 2237: 2234: 2231: 2228: 2225: 2219: 2211: 2201: 2184: 2181: 2165: 2127: 2121: 2118: 2100: 2083: 2080: 2046: 2043: 2033:the interval 2020: 2014: 2011: 2008: 2002: 1990: 1989: 1988: 1974: 1971: 1968: 1948: 1945: 1942: 1939: 1912: 1909: 1887: 1875: 1872: 1852: 1848: 1844: 1841: 1836: 1823: 1778: 1769: 1766: 1750: 1738: 1724:). A subset 1710: 1688: 1667: 1664: 1661: 1641: 1638: 1635: 1628:declare that 1615: 1612: 1592: 1570: 1553: 1552:partial order 1536: 1527: 1511: 1508: 1505: 1502: 1494: 1476: 1459: 1443: 1431: 1430: 1429: 1428:is directed. 1412: 1409: 1406: 1381: 1377: 1373: 1370: 1367: 1362: 1358: 1335: 1331: 1327: 1324: 1321: 1316: 1312: 1288: 1285: 1282: 1270: 1262: 1245: 1242: 1239: 1216: 1196: 1193: 1190: 1182: 1163: 1160: 1157: 1145: 1132: 1129: 1121: 1105: 1097: 1081: 1072: 1070: 1066: 1060: 1058: 1054: 1049: 1036: 1033: 1013: 993: 973: 953: 933: 913: 910: 890: 882: 878: 874: 864: 862: 858: 854: 835: 832: 829: 826: 806: 803: 800: 780: 777: 774: 771: 763: 762: 761: 759: 753: 749: 735: 732: 729: 717: 716: 715: 702: 699: 679: 656: 650: 643: 637: 623: 617: 614: 611: 604: 596: 595: 594: 592: 589:, which is a 588: 569: 566: 563: 550: 533: 530: 527: 524: 504: 501: 498: 478: 475: 472: 469: 461: 460: 459: 444: 433: 429: 415: 412: 409: 389: 386: 378: 361: 346: 333: 330: 322: 306: 298: 294: 290: 286: 282: 278: 274: 273:directed sets 269: 255: 252: 249: 229: 209: 189: 169: 149: 146: 143: 140: 133:if for every 120: 112: 108: 89: 86: 83: 73: 57: 54: 51: 44: 40: 30: 19: 4040:Order theory 3891: 3811:& Orders 3789:Star product 3718:Well-founded 3671:Prefix order 3627:Distributive 3617:Complemented 3587:Foundational 3552:Completeness 3508:Zorn's lemma 3412:Cyclic order 3395:Key concepts 3365:Order theory 3308: 3279: 3262: 3259:Bredon, Glen 3253: 2885: 2687:of some set 2634: 2480:but this is 2272: 2200:but this is 1994: 1765:is called a 1702:is equal to 1435: 1271: 1268: 1181:directed set 1146: 1120:well-ordered 1073: 1050: 870: 851:This is the 850: 721: 600: 587:directed set 548: 352: 289:order theory 270: 110: 106: 36: 3995:Riesz space 3956:Isomorphism 3832:Normal cone 3754:Composition 3688:Semilattice 3597:Homogeneous 3582:Equivalence 3432:Total order 3276:Lang, Serge 2829:there is a 1495:at a point 1491:denote the 986:applied to 349:Definitions 297:cardinality 285:subsequence 39:mathematics 18:Cofinal set 3963:Order type 3897:Cofinality 3738:Well-order 3713:Transitive 3602:Idempotent 3535:Asymmetric 3298:0848.13001 3222:References 3075:Cofinality 2970:of finite 2934:of finite 2855:such that 2380:but it is 2099:but it is 1932:such that 881:transitive 867:Properties 857:dense sets 819:such that 764:For every 551:infrequent 462:For every 321:cofinality 4014:Upper set 3951:Embedding 3887:Antichain 3708:Tolerance 3698:Symmetric 3693:Semiorder 3639:Reflexive 3557:Connected 3327:175294365 3201:≤ 3175:∈ 3149:∈ 3123:≤ 3086:a subset 3081:Upper set 2972:quotients 2866:⊇ 2840:∈ 2814:∈ 2768:⊆ 2757:a subset 2719:⊇ 2666:℘ 2657:power set 2588:≥ 2554:≤ 2465:≥ 2429:− 2403:≤ 2365:≥ 2325:∞ 2322:− 2296:∞ 2284:∞ 2281:− 2253:… 2244:− 2235:− 2226:− 2212:− 2185:≤ 2122:≥ 2084:≤ 2050:∞ 2018:∞ 2006:∞ 2003:− 1972:≤ 1943:⊇ 1913:∈ 1876:∈ 1845:⊇ 1739:⊆ 1711:⊇ 1689:≤ 1665:⊇ 1639:≤ 1537:⊇ 1528:relation 1506:∈ 1413:≤ 1371:… 1328:∪ 1325:⋯ 1322:∪ 1289:≤ 1246:≤ 1194:⊆ 1164:≤ 1094:admits a 877:reflexive 830:≤ 804:∈ 775:∈ 750:coinitial 733:⊆ 722:A subset 621:→ 570:≤ 528:≤ 502:∈ 473:∈ 445:≤ 413:⊆ 402:A subset 379:on a set 362:≤ 279:, where “ 253:≤ 144:∈ 90:≤ 55:⊆ 4034:Category 3809:Topology 3676:Preorder 3659:Eulerian 3622:Complete 3572:Directed 3562:Covering 3427:Preorder 3386:Category 3381:Glossary 3307:(1996). 3278:(1993), 3261:(1993). 3066:Cofinite 3060:See also 2910:and let 2533:integers 2509:The set 2421:The set 2140:The set 1995:For any 1526:superset 1460:and let 1118:that is 1006:), then 434:frequent 242:" means 111:frequent 29:cofinite 3914:Duality 3892:Cofinal 3880:Related 3859:FrĂ©chet 3736:)  3612:Bounded 3607:Lattice 3580:)  3578:Partial 3446:Results 3417:Lattice 3280:Algebra 2966:of the 2531:of all 1183:and if 758:forcing 640:if the 430:cofinal 107:cofinal 3939:Subnet 3919:Filter 3869:Normed 3854:Banach 3820:& 3727:Better 3664:Strict 3654:Graded 3545:topics 3376:Topics 3325:  3315:  3296:  3286:  2938:. The 875:") is 873:posets 43:subset 3929:Ideal 3907:Graph 3703:Total 3681:Total 3567:Dense 3190:with 2936:index 2908:group 2906:be a 1550:is a 1456:be a 1229:then 1179:is a 883:: if 754:dense 642:image 638:final 585:is a 517:that 375:be a 70:of a 3520:list 3323:OCLC 3313:ISBN 3284:ISBN 2293:< 2287:< 2015:< 2009:< 1605:and 1524:The 1436:Let 926:and 752:(or 353:Let 277:nets 275:and 268:). 41:, a 3934:Net 3734:Pre 3294:Zbl 2974:of 2942:of 2482:not 2382:not 2202:not 2162:of 2101:not 1987:.) 1771:at 1554:on 1272:If 1147:If 672:of 603:map 432:or 323:of 182:in 113:in 109:or 37:In 4036:: 3321:. 3292:, 3230:^ 2220::= 863:. 601:A 3732:( 3729:) 3725:( 3576:( 3523:) 3357:e 3350:t 3343:v 3329:. 3204:y 3198:x 3178:U 3172:x 3152:P 3146:y 3126:) 3120:, 3117:P 3114:( 3094:U 3045:. 3042:E 3022:A 3002:A 2982:E 2950:E 2918:A 2894:E 2872:. 2869:b 2863:a 2843:B 2837:b 2817:A 2811:a 2791:A 2771:A 2765:B 2745:, 2742:A 2722:. 2698:, 2695:E 2675:) 2672:E 2669:( 2643:A 2616:. 2612:Q 2591:) 2585:, 2581:R 2577:( 2557:) 2551:, 2547:R 2543:( 2518:Z 2497:. 2493:N 2468:) 2462:, 2458:R 2454:( 2433:N 2409:. 2406:) 2400:, 2396:R 2392:( 2368:) 2362:, 2358:R 2354:( 2334:) 2331:y 2328:, 2319:( 2299:, 2290:y 2259:. 2256:} 2250:, 2247:3 2241:, 2238:2 2232:, 2229:1 2223:{ 2216:N 2188:) 2182:, 2178:R 2174:( 2149:N 2128:. 2125:) 2119:, 2115:R 2111:( 2087:) 2081:, 2077:R 2073:( 2053:) 2047:, 2044:x 2041:( 2021:, 2012:x 1975:B 1969:N 1949:. 1946:B 1940:N 1918:B 1910:B 1888:x 1882:N 1873:N 1853:; 1849:) 1842:, 1837:x 1831:N 1824:( 1801:B 1779:x 1751:x 1745:N 1734:B 1668:T 1662:S 1642:T 1636:S 1616:, 1613:T 1593:S 1571:x 1565:N 1512:. 1509:X 1503:x 1477:x 1471:N 1444:X 1416:) 1410:, 1407:A 1404:( 1382:n 1378:S 1374:, 1368:, 1363:1 1359:S 1336:n 1332:S 1317:1 1313:S 1292:) 1286:, 1283:A 1280:( 1249:) 1243:, 1240:B 1237:( 1217:A 1197:A 1191:B 1167:) 1161:, 1158:A 1155:( 1133:. 1130:A 1106:B 1082:A 1037:. 1034:A 1014:C 994:B 974:A 954:B 934:C 914:, 911:A 891:B 836:. 833:a 827:b 807:B 801:b 781:, 778:A 772:a 736:A 730:B 703:. 700:A 680:f 660:) 657:X 654:( 651:f 624:A 618:X 615:: 612:f 573:) 567:, 564:A 561:( 534:. 531:b 525:a 505:B 499:b 479:, 476:A 470:a 416:A 410:B 390:. 387:A 334:. 331:A 307:A 256:b 250:a 230:a 210:a 190:B 170:b 150:, 147:A 141:a 121:A 93:) 87:, 84:A 81:( 58:A 52:B 31:. 20:)

Index

Cofinal set
cofinite
mathematics
subset
preordered set
directed sets
nets
cofinal subnet
subsequence
order theory
cardinal numbers
cardinality
cofinality
homogeneous binary relation
directed set
preordered set
map
image
forcing
order-theoretic dual
dense sets
order topology
posets
reflexive
transitive
maximal elements
maximal elements
greatest element
natural numbers
totally ordered

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