Knowledge (XXG)

Disjoint union

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As such, the disjoint union is defined up to an isomorphism, and the above definition is just one realization of the coproduct, among others. When the sets are pairwise disjoint, the usual union is another realization of the coproduct. This justifies the second definition in the lead.
1313: 1612: 1808: 248: 867: 2616: 2025: 765: 2380: 1151: 1146: 1668: 448: 808: 2425: 1442: 624: 1704: 1437: 147: 1093: 1035: 1141: 379: 2682: 961: 994: 2535: 2145: 2113: 723: 697: 291: 72: 3336: 2659: 2081: 2278: 1846: 1397: 2566: 2229: 2199: 2172: 2052: 1943: 1893: 1367: 925: 479: 2451: 1695: 502: 402: 2322: 2302: 2249: 1913: 1866: 1335: 890: 667: 647: 550: 530: 1948: 3486: 2796: 3025: 2845: 2730: 813: 2571: 2327: 3353: 2712: â€“ space formed by equipping the disjoint union of the underlying sets with a natural topology called the disjoint union topology 94: 3331: 728: 3105: 2984: 2788: 3348: 2387: 3341: 55: 3491: 2979: 2942: 1308:{\displaystyle {\begin{aligned}A_{0}^{*}&=\{(5,0),(6,0),(7,0)\}\\A_{1}^{*}&=\{(5,1),(6,1)\},\\\end{aligned}}} 65: 59: 51: 3030: 2922: 2910: 2905: 2724: 2709: 76: 2838: 2763: 2718: 1624: 24: 3450: 3368: 3243: 3195: 3009: 2932: 2791:, vol. 211 (Corrected fourth printing, revised third ed.), New York: Springer-Verlag, p. 60, 407: 3402: 3283: 3095: 2915: 770: 553: 509: 3318: 3232: 3152: 3132: 3110: 586: 1402: 3392: 3382: 3216: 3147: 3100: 3040: 2927: 2751: 1047: 999: 1098: 339: 3387: 3298: 3211: 3206: 3201: 3015: 2957: 2895: 2831: 505: 317:
labelled (indexed) with the name of the set from which they come. So, an element belonging to both
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For many purposes, the particular choice of auxiliary index is unimportant, and in a simplifying
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for the disjoint union of two sets. This notation is meant to be suggestive of the fact that the
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where the second element in each pair matches the subscript of the origin set (for example, the
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It is possible to index the set elements according to set origin by forming the associated sets
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This article is about the operation on sets. For the computer science meaning of the term, see
3167: 3004: 2996: 2967: 2937: 2868: 2806: 2792: 2644: 2502: 2489: 2462: 2281: 2057: 135: 125: 31: 2254: 3455: 3445: 3430: 3425: 3293: 2947: 2485: 2477: 1816: 1607:{\displaystyle A_{0}\sqcup A_{1}=A_{0}^{*}\cup A_{1}^{*}=\{(5,0),(6,0),(7,0),(5,1),(6,1)\}.} 1372: 572: 2544: 2207: 2177: 2150: 2030: 1921: 1871: 1340: 898: 457: 3324: 3262: 3080: 2900: 2627: 2469: 1803:{\displaystyle \bigsqcup _{i\in I}A_{i}=\bigcup _{i\in I}\left\{(x,i):x\in A_{i}\right\}.} 564: 114: 2430: 243:{\displaystyle \bigsqcup _{i\in I}A_{i}=\bigcup _{i\in I}\left\{(x,i):x\in A_{i}\right\}} 1677: 484: 384: 3460: 3257: 3238: 3142: 3127: 3084: 2962: 2307: 2287: 2234: 1898: 1851: 1671: 1320: 875: 670: 652: 632: 535: 515: 333: 2766: â€“ Data type that allows for values that are one of multiple different data types 2461:
of the cardinalities of the terms in the family. Compare this to the notation for the
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belongs to exactly one of these images). A disjoint union of a family of
862:{\textstyle \operatorname {{\bigcup }\!\!\!{\cdot }\,} _{i\in I}A_{i}} 3248: 3070: 2427:
is used for the disjoint union of a family of sets, or the notation
2611:{\displaystyle {\underset {A\in C}{\,\,\bigcup \nolimits ^{*}\!}}A} 3120: 2887: 576: 329:
appears twice in the disjoint union, with two different labels.
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A standard way for building the disjoint union is to define
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This categorical aspect of the disjoint union explains why
2020:{\displaystyle A_{i}^{*}=\left\{(x,i):x\in A_{i}\right\}.} 760:{\displaystyle A\operatorname {{\cup }\!\!\!{\cdot }\,} B} 2721: â€“ Combining the vertex and edge sets of two graphs 2768:
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is canonically embedded in the disjoint union. For
3401: 3364: 3276: 3166: 3054: 2995: 2886: 2861: 2375:{\displaystyle \bigsqcup _{i\in I}A_{i}=A\times I.} 141: 131: 121: 2727: â€“ Set of elements common to all of some sets 2706: â€“ Special case of colimit in category theory 2676: 2653: 2610: 2560: 2529: 2445: 2419: 2374: 2316: 2296: 2272: 2243: 2223: 2193: 2166: 2139: 2107: 2075: 2046: 2019: 1937: 1907: 1887: 1868:serves as an auxiliary index that indicates which 1860: 1840: 1802: 1689: 1662: 1606: 1431: 1391: 1361: 1329: 1307: 1135: 1087: 1029: 988: 955: 919: 884: 861: 802: 759: 717: 691: 661: 641: 618: 544: 524: 496: 473: 442: 396: 373: 285: 242: 2590: 2484:. This also means that the disjoint union is the 826: 825: 824: 743: 742: 741: 2027:Through this isomorphism, one may consider that 64:but its sources remain unclear because it lacks 2839: 699:. Some authors use the alternative notation 8: 1598: 1508: 1295: 1259: 1230: 1176: 1127: 1115: 1082: 1064: 107: 2754: â€“ Elements in exactly one of two sets 2733: â€“ Equalities for combinations of sets 2846: 2832: 2824: 113: 106: 2666: 2646: 2584: 2579: 2578: 2575: 2573: 2552: 2546: 2521: 2516: 2510: 2432: 2411: 2395: 2389: 2351: 2335: 2329: 2309: 2289: 2256: 2236: 2215: 2209: 2185: 2179: 2158: 2152: 2131: 2126: 2120: 2099: 2094: 2088: 2059: 2038: 2032: 2003: 1961: 1956: 1950: 1929: 1923: 1900: 1879: 1873: 1853: 1818: 1786: 1741: 1728: 1712: 1706: 1679: 1663:{\displaystyle \left(A_{i}:i\in I\right)} 1637: 1626: 1499: 1494: 1481: 1476: 1463: 1450: 1444: 1423: 1410: 1404: 1380: 1374: 1342: 1322: 1246: 1241: 1163: 1158: 1150: 1148: 1106: 1100: 1055: 1049: 1001: 974: 968: 944: 932: 900: 877: 853: 834: 832: 827: 819: 818: 815: 794: 778: 772: 749: 744: 736: 735: 730: 704: 678: 654: 634: 610: 594: 588: 537: 517: 486: 465: 459: 431: 415: 409: 386: 350: 341: 272: 229: 184: 171: 155: 149: 95:Learn how and when to remove this message 2480:. It therefore satisfies the associated 2700: â€“ Category-theoretic construction 1810:The elements of the disjoint union are 305:is the set formed from the elements of 2204:In the extreme case where each of the 443:{\textstyle \bigsqcup _{i\in I}A_{i},} 1945:is canonically isomorphic to the set 803:{\textstyle \biguplus _{i\in I}A_{i}} 7: 2731:List of set identities and relations 2630:the disjoint union is defined as a 2581: 2420:{\displaystyle \sum _{i\in I}A_{i}} 1439:can then be calculated as follows: 619:{\textstyle \coprod _{i\in I}A_{i}} 23:. For the operation on graphs, see 14: 1432:{\displaystyle A_{0}\sqcup A_{1}} 583:. In this context, the notation 16:In mathematics, operation on sets 2877: 41: 2661:is frequently used, instead of 1088:{\displaystyle A_{0}=\{5,6,7\}} 1030:{\displaystyle x\mapsto (x,i).} 629:The disjoint union of two sets 2147:are disjoint even if the sets 1987: 1975: 1832: 1820: 1770: 1758: 1595: 1583: 1577: 1565: 1559: 1547: 1541: 1529: 1523: 1511: 1356: 1344: 1292: 1280: 1274: 1262: 1227: 1215: 1209: 1197: 1191: 1179: 1136:{\displaystyle A_{1}=\{5,6\}.} 1021: 1009: 1006: 980: 914: 902: 767:(along with the corresponding 374:{\displaystyle (A_{i}:i\in I)} 368: 343: 213: 201: 1: 2789:Graduate Texts in Mathematics 2622:Category theory point of view 2457:of the disjoint union is the 3487:Basic concepts in set theory 2472:, the disjoint union is the 567:, the disjoint union is the 2677:{\displaystyle \bigsqcup ,} 2384:Occasionally, the notation 2231:is equal to some fixed set 956:{\displaystyle x\in A_{i},} 508:of these injections form a 3510: 3337:von Neumann–Bernays–Gödel 2634:in the category of sets. 2280:the disjoint union is the 1701:of this family is the set 1399:etc.). The disjoint union 989:{\displaystyle A_{i}\to A} 532:(that is, each element of 29: 18: 3138:One-to-one correspondence 2875: 2725:Intersection (set theory) 2710:Disjoint union (topology) 2530:{\displaystyle A_{i}^{*}} 2140:{\displaystyle A_{j}^{*}} 2108:{\displaystyle A_{i}^{*}} 1369:matches the subscript in 718:{\displaystyle A\uplus B} 692:{\displaystyle A\sqcup B} 286:{\displaystyle A\sqcup B} 112: 2764:Union (computer science) 2719:Disjoint union of graphs 2654:{\displaystyle \coprod } 2076:{\displaystyle i\neq j,} 50:This article includes a 30:Not to be confused with 25:disjoint union of graphs 2273:{\displaystyle i\in I,} 332:A disjoint union of an 79:more precise citations. 3096:Constructible universe 2923:Constructibility (V=L) 2678: 2655: 2612: 2562: 2531: 2465:of a family of sets. 2447: 2421: 2376: 2318: 2298: 2274: 2245: 2225: 2195: 2168: 2141: 2109: 2077: 2048: 2021: 1939: 1909: 1889: 1862: 1842: 1841:{\displaystyle (x,i).} 1804: 1691: 1664: 1608: 1433: 1393: 1392:{\displaystyle A_{0},} 1363: 1331: 1309: 1137: 1089: 1031: 990: 957: 921: 886: 863: 804: 761: 719: 693: 663: 643: 620: 554:pairwise disjoint sets 546: 526: 498: 475: 444: 398: 375: 287: 244: 3319:Principia Mathematica 3153:Transfinite induction 3012:(i.e. set difference) 2679: 2656: 2613: 2563: 2561:{\displaystyle A_{i}} 2532: 2448: 2422: 2377: 2319: 2299: 2275: 2246: 2226: 2224:{\displaystyle A_{i}} 2196: 2194:{\displaystyle A_{j}} 2169: 2167:{\displaystyle A_{i}} 2142: 2110: 2078: 2049: 2047:{\displaystyle A_{i}} 2022: 1940: 1938:{\displaystyle A_{i}} 1910: 1890: 1888:{\displaystyle A_{i}} 1863: 1843: 1805: 1692: 1665: 1617:Set theory definition 1609: 1434: 1394: 1364: 1362:{\displaystyle (5,0)} 1332: 1310: 1138: 1090: 1032: 991: 958: 922: 920:{\displaystyle (x,i)} 887: 864: 805: 762: 720: 694: 664: 644: 621: 547: 527: 499: 476: 474:{\displaystyle A_{i}} 445: 399: 376: 288: 245: 3393:Burali-Forti paradox 3148:Set-builder notation 3101:Continuum hypothesis 3041:Symmetric difference 2752:Symmetric difference 2665: 2645: 2572: 2545: 2537:is referred to as a 2509: 2431: 2388: 2328: 2308: 2288: 2255: 2235: 2208: 2178: 2151: 2119: 2087: 2058: 2031: 1949: 1922: 1899: 1872: 1852: 1817: 1705: 1678: 1625: 1443: 1403: 1373: 1341: 1321: 1147: 1099: 1048: 1000: 967: 931: 899: 876: 814: 771: 729: 703: 677: 653: 633: 587: 536: 516: 485: 458: 408: 385: 340: 271: 148: 3354:Tarski–Grothendieck 2618:is sometimes used. 2526: 2468:In the language of 2446:{\displaystyle A+B} 2136: 2104: 1966: 1674:of sets indexed by 1504: 1486: 1251: 1168: 575:, and thus defined 265:discriminated union 109: 3492:Operations on sets 2943:Limitation of size 2807:Weisstein, Eric W. 2737:Partition of a set 2674: 2651: 2608: 2603: 2558: 2527: 2512: 2498:for more details. 2492:construction. See 2482:universal property 2443: 2417: 2406: 2372: 2346: 2314: 2294: 2270: 2241: 2221: 2191: 2164: 2137: 2122: 2105: 2090: 2073: 2044: 2017: 1952: 1935: 1905: 1885: 1858: 1838: 1800: 1752: 1723: 1690:{\displaystyle I.} 1687: 1660: 1604: 1490: 1472: 1429: 1389: 1359: 1327: 1305: 1303: 1237: 1154: 1133: 1085: 1044:Consider the sets 1027: 986: 963:and the injection 953: 917: 882: 859: 800: 789: 757: 715: 689: 659: 639: 616: 605: 542: 522: 497:{\displaystyle A,} 494: 471: 440: 426: 397:{\displaystyle A,} 394: 371: 283: 240: 195: 166: 142:Symbolic statement 52:list of references 3474: 3473: 3383:Russell's paradox 3332:Zermelo–Fraenkel 3233:Dedekind-infinite 3106:Diagonal argument 3005:Cartesian product 2869:Set (mathematics) 2798:978-0-387-95385-4 2576: 2568:and the notation 2503:abuse of notation 2490:Cartesian product 2463:Cartesian product 2391: 2331: 2317:{\displaystyle I} 2297:{\displaystyle A} 2282:Cartesian product 2244:{\displaystyle A} 1918:Each of the sets 1908:{\displaystyle x} 1861:{\displaystyle i} 1737: 1708: 1330:{\displaystyle 0} 885:{\displaystyle A} 774: 662:{\displaystyle B} 642:{\displaystyle A} 590: 545:{\displaystyle A} 525:{\displaystyle A} 411: 404:often denoted by 253: 252: 180: 151: 105: 104: 97: 32:Disjunctive union 3499: 3456:Bertrand Russell 3446:John von Neumann 3431:Abraham Fraenkel 3426:Richard Dedekind 3388:Suslin's problem 3299:Cantor's theorem 3016:De Morgan's laws 2881: 2848: 2841: 2834: 2825: 2820: 2819: 2810:"Disjoint Union" 2801: 2769: 2748: 2715: 2683: 2681: 2680: 2675: 2660: 2658: 2657: 2652: 2617: 2615: 2614: 2609: 2604: 2602: 2591: 2589: 2588: 2567: 2565: 2564: 2559: 2557: 2556: 2536: 2534: 2533: 2528: 2525: 2520: 2486:categorical dual 2478:category of sets 2452: 2450: 2449: 2444: 2426: 2424: 2423: 2418: 2416: 2415: 2405: 2381: 2379: 2378: 2373: 2356: 2355: 2345: 2323: 2321: 2320: 2315: 2303: 2301: 2300: 2295: 2279: 2277: 2276: 2271: 2250: 2248: 2247: 2242: 2230: 2228: 2227: 2222: 2220: 2219: 2200: 2198: 2197: 2192: 2190: 2189: 2173: 2171: 2170: 2165: 2163: 2162: 2146: 2144: 2143: 2138: 2135: 2130: 2114: 2112: 2111: 2106: 2103: 2098: 2082: 2080: 2079: 2074: 2053: 2051: 2050: 2045: 2043: 2042: 2026: 2024: 2023: 2018: 2013: 2009: 2008: 2007: 1965: 1960: 1944: 1942: 1941: 1936: 1934: 1933: 1914: 1912: 1911: 1906: 1894: 1892: 1891: 1886: 1884: 1883: 1867: 1865: 1864: 1859: 1847: 1845: 1844: 1839: 1809: 1807: 1806: 1801: 1796: 1792: 1791: 1790: 1751: 1733: 1732: 1722: 1696: 1694: 1693: 1688: 1669: 1667: 1666: 1661: 1659: 1655: 1642: 1641: 1613: 1611: 1610: 1605: 1503: 1498: 1485: 1480: 1468: 1467: 1455: 1454: 1438: 1436: 1435: 1430: 1428: 1427: 1415: 1414: 1398: 1396: 1395: 1390: 1385: 1384: 1368: 1366: 1365: 1360: 1336: 1334: 1333: 1328: 1314: 1312: 1311: 1306: 1304: 1250: 1245: 1167: 1162: 1142: 1140: 1139: 1134: 1111: 1110: 1094: 1092: 1091: 1086: 1060: 1059: 1036: 1034: 1033: 1028: 995: 993: 992: 987: 979: 978: 962: 960: 959: 954: 949: 948: 926: 924: 923: 918: 891: 889: 888: 883: 868: 866: 865: 860: 858: 857: 845: 844: 833: 831: 823: 809: 807: 806: 801: 799: 798: 788: 766: 764: 763: 758: 750: 748: 740: 724: 722: 721: 716: 698: 696: 695: 690: 669:is written with 668: 666: 665: 660: 648: 646: 645: 640: 625: 623: 622: 617: 615: 614: 604: 573:category of sets 551: 549: 548: 543: 531: 529: 528: 523: 503: 501: 500: 495: 480: 478: 477: 472: 470: 469: 449: 447: 446: 441: 436: 435: 425: 403: 401: 400: 395: 380: 378: 377: 372: 355: 354: 328: 322: 316: 310: 304: 298: 292: 290: 289: 284: 249: 247: 246: 241: 239: 235: 234: 233: 194: 176: 175: 165: 117: 110: 100: 93: 89: 86: 80: 75:this article by 66:inline citations 45: 44: 37: 3509: 3508: 3502: 3501: 3500: 3498: 3497: 3496: 3477: 3476: 3475: 3470: 3397: 3376: 3360: 3325:New Foundations 3272: 3162: 3081:Cardinal number 3064: 3050: 2991: 2882: 2873: 2857: 2852: 2805: 2804: 2799: 2779: 2776: 2767: 2746: 2713: 2694: 2663: 2662: 2643: 2642: 2628:category theory 2624: 2592: 2580: 2577: 2570: 2569: 2548: 2543: 2542: 2507: 2506: 2470:category theory 2429: 2428: 2407: 2386: 2385: 2347: 2326: 2325: 2306: 2305: 2286: 2285: 2253: 2252: 2233: 2232: 2211: 2206: 2205: 2181: 2176: 2175: 2154: 2149: 2148: 2117: 2116: 2085: 2084: 2056: 2055: 2034: 2029: 2028: 1999: 1974: 1970: 1947: 1946: 1925: 1920: 1919: 1897: 1896: 1875: 1870: 1869: 1850: 1849: 1815: 1814: 1782: 1757: 1753: 1724: 1703: 1702: 1676: 1675: 1633: 1632: 1628: 1623: 1622: 1619: 1459: 1446: 1441: 1440: 1419: 1406: 1401: 1400: 1376: 1371: 1370: 1339: 1338: 1319: 1318: 1302: 1301: 1252: 1234: 1233: 1169: 1145: 1144: 1102: 1097: 1096: 1051: 1046: 1045: 1042: 998: 997: 970: 965: 964: 940: 929: 928: 897: 896: 874: 873: 849: 817: 812: 811: 790: 769: 768: 727: 726: 701: 700: 675: 674: 651: 650: 631: 630: 626:is often used. 606: 585: 584: 565:category theory 534: 533: 514: 513: 483: 482: 461: 456: 455: 427: 406: 405: 383: 382: 346: 338: 337: 324: 318: 312: 306: 300: 294: 269: 268: 225: 200: 196: 167: 146: 145: 101: 90: 84: 81: 70: 56:related reading 46: 42: 35: 28: 17: 12: 11: 5: 3507: 3506: 3503: 3495: 3494: 3489: 3479: 3478: 3472: 3471: 3469: 3468: 3463: 3461:Thoralf Skolem 3458: 3453: 3448: 3443: 3438: 3433: 3428: 3423: 3418: 3413: 3407: 3405: 3399: 3398: 3396: 3395: 3390: 3385: 3379: 3377: 3375: 3374: 3371: 3365: 3362: 3361: 3359: 3358: 3357: 3356: 3351: 3346: 3345: 3344: 3329: 3328: 3327: 3315: 3314: 3313: 3302: 3301: 3296: 3291: 3286: 3280: 3278: 3274: 3273: 3271: 3270: 3265: 3260: 3255: 3246: 3241: 3236: 3226: 3221: 3220: 3219: 3214: 3209: 3199: 3189: 3184: 3179: 3173: 3171: 3164: 3163: 3161: 3160: 3155: 3150: 3145: 3143:Ordinal number 3140: 3135: 3130: 3125: 3124: 3123: 3118: 3108: 3103: 3098: 3093: 3088: 3078: 3073: 3067: 3065: 3063: 3062: 3059: 3055: 3052: 3051: 3049: 3048: 3043: 3038: 3033: 3028: 3023: 3021:Disjoint union 3018: 3013: 3007: 3001: 2999: 2993: 2992: 2990: 2989: 2988: 2987: 2982: 2971: 2970: 2968:Martin's axiom 2965: 2960: 2955: 2950: 2945: 2940: 2935: 2933:Extensionality 2930: 2925: 2920: 2919: 2918: 2913: 2908: 2898: 2892: 2890: 2884: 2883: 2876: 2874: 2872: 2871: 2865: 2863: 2859: 2858: 2853: 2851: 2850: 2843: 2836: 2828: 2822: 2821: 2802: 2797: 2775: 2772: 2771: 2770: 2761: 2755: 2749: 2740: 2734: 2728: 2722: 2716: 2707: 2701: 2693: 2690: 2673: 2670: 2650: 2623: 2620: 2607: 2601: 2598: 2595: 2587: 2583: 2555: 2551: 2540: 2524: 2519: 2515: 2442: 2439: 2436: 2414: 2410: 2404: 2401: 2398: 2394: 2371: 2368: 2365: 2362: 2359: 2354: 2350: 2344: 2341: 2338: 2334: 2313: 2293: 2269: 2266: 2263: 2260: 2240: 2218: 2214: 2188: 2184: 2161: 2157: 2134: 2129: 2125: 2102: 2097: 2093: 2072: 2069: 2066: 2063: 2041: 2037: 2016: 2012: 2006: 2002: 1998: 1995: 1992: 1989: 1986: 1983: 1980: 1977: 1973: 1969: 1964: 1959: 1955: 1932: 1928: 1904: 1882: 1878: 1857: 1837: 1834: 1831: 1828: 1825: 1822: 1799: 1795: 1789: 1785: 1781: 1778: 1775: 1772: 1769: 1766: 1763: 1760: 1756: 1750: 1747: 1744: 1740: 1736: 1731: 1727: 1721: 1718: 1715: 1711: 1699:disjoint union 1686: 1683: 1672:indexed family 1658: 1654: 1651: 1648: 1645: 1640: 1636: 1631: 1621:Formally, let 1618: 1615: 1603: 1600: 1597: 1594: 1591: 1588: 1585: 1582: 1579: 1576: 1573: 1570: 1567: 1564: 1561: 1558: 1555: 1552: 1549: 1546: 1543: 1540: 1537: 1534: 1531: 1528: 1525: 1522: 1519: 1516: 1513: 1510: 1507: 1502: 1497: 1493: 1489: 1484: 1479: 1475: 1471: 1466: 1462: 1458: 1453: 1449: 1426: 1422: 1418: 1413: 1409: 1388: 1383: 1379: 1358: 1355: 1352: 1349: 1346: 1326: 1300: 1297: 1294: 1291: 1288: 1285: 1282: 1279: 1276: 1273: 1270: 1267: 1264: 1261: 1258: 1255: 1253: 1249: 1244: 1240: 1236: 1235: 1232: 1229: 1226: 1223: 1220: 1217: 1214: 1211: 1208: 1205: 1202: 1199: 1196: 1193: 1190: 1187: 1184: 1181: 1178: 1175: 1172: 1170: 1166: 1161: 1157: 1153: 1152: 1132: 1129: 1126: 1123: 1120: 1117: 1114: 1109: 1105: 1084: 1081: 1078: 1075: 1072: 1069: 1066: 1063: 1058: 1054: 1041: 1038: 1026: 1023: 1020: 1017: 1014: 1011: 1008: 1005: 985: 982: 977: 973: 952: 947: 943: 939: 936: 916: 913: 910: 907: 904: 892:as the set of 881: 856: 852: 848: 843: 840: 837: 830: 822: 797: 793: 787: 784: 781: 777: 756: 753: 747: 739: 734: 714: 711: 708: 688: 685: 682: 671:infix notation 658: 638: 613: 609: 603: 600: 597: 593: 541: 521: 504:such that the 493: 490: 468: 464: 439: 434: 430: 424: 421: 418: 414: 393: 390: 370: 367: 364: 361: 358: 353: 349: 345: 334:indexed family 282: 279: 276: 261:disjoint union 251: 250: 238: 232: 228: 224: 221: 218: 215: 212: 209: 206: 203: 199: 193: 190: 187: 183: 179: 174: 170: 164: 161: 158: 154: 143: 139: 138: 133: 129: 128: 123: 119: 118: 108:Disjoint union 103: 102: 60:external links 49: 47: 40: 15: 13: 10: 9: 6: 4: 3: 2: 3505: 3504: 3493: 3490: 3488: 3485: 3484: 3482: 3467: 3466:Ernst Zermelo 3464: 3462: 3459: 3457: 3454: 3452: 3451:Willard Quine 3449: 3447: 3444: 3442: 3439: 3437: 3434: 3432: 3429: 3427: 3424: 3422: 3419: 3417: 3414: 3412: 3409: 3408: 3406: 3404: 3403:Set theorists 3400: 3394: 3391: 3389: 3386: 3384: 3381: 3380: 3378: 3372: 3370: 3367: 3366: 3363: 3355: 3352: 3350: 3349:Kripke–Platek 3347: 3343: 3340: 3339: 3338: 3335: 3334: 3333: 3330: 3326: 3323: 3322: 3321: 3320: 3316: 3312: 3309: 3308: 3307: 3304: 3303: 3300: 3297: 3295: 3292: 3290: 3287: 3285: 3282: 3281: 3279: 3275: 3269: 3266: 3264: 3261: 3259: 3256: 3254: 3252: 3247: 3245: 3242: 3240: 3237: 3234: 3230: 3227: 3225: 3222: 3218: 3215: 3213: 3210: 3208: 3205: 3204: 3203: 3200: 3197: 3193: 3190: 3188: 3185: 3183: 3180: 3178: 3175: 3174: 3172: 3169: 3165: 3159: 3156: 3154: 3151: 3149: 3146: 3144: 3141: 3139: 3136: 3134: 3131: 3129: 3126: 3122: 3119: 3117: 3114: 3113: 3112: 3109: 3107: 3104: 3102: 3099: 3097: 3094: 3092: 3089: 3086: 3082: 3079: 3077: 3074: 3072: 3069: 3068: 3066: 3060: 3057: 3056: 3053: 3047: 3044: 3042: 3039: 3037: 3034: 3032: 3029: 3027: 3024: 3022: 3019: 3017: 3014: 3011: 3008: 3006: 3003: 3002: 3000: 2998: 2994: 2986: 2985:specification 2983: 2981: 2978: 2977: 2976: 2973: 2972: 2969: 2966: 2964: 2961: 2959: 2956: 2954: 2951: 2949: 2946: 2944: 2941: 2939: 2936: 2934: 2931: 2929: 2926: 2924: 2921: 2917: 2914: 2912: 2909: 2907: 2904: 2903: 2902: 2899: 2897: 2894: 2893: 2891: 2889: 2885: 2880: 2870: 2867: 2866: 2864: 2860: 2856: 2849: 2844: 2842: 2837: 2835: 2830: 2829: 2826: 2817: 2816: 2811: 2808: 2803: 2800: 2794: 2790: 2786: 2782: 2778: 2777: 2773: 2765: 2762: 2759: 2756: 2753: 2750: 2744: 2741: 2738: 2735: 2732: 2729: 2726: 2723: 2720: 2717: 2711: 2708: 2705: 2702: 2699: 2696: 2695: 2691: 2689: 2687: 2671: 2668: 2648: 2639: 2635: 2633: 2629: 2621: 2619: 2605: 2599: 2596: 2593: 2585: 2553: 2549: 2538: 2522: 2517: 2513: 2504: 2499: 2497: 2496: 2491: 2487: 2483: 2479: 2475: 2471: 2466: 2464: 2460: 2456: 2440: 2437: 2434: 2412: 2408: 2402: 2399: 2396: 2392: 2382: 2369: 2366: 2363: 2360: 2357: 2352: 2348: 2342: 2339: 2336: 2332: 2311: 2291: 2283: 2267: 2264: 2261: 2258: 2238: 2216: 2212: 2202: 2186: 2182: 2159: 2155: 2132: 2127: 2123: 2100: 2095: 2091: 2070: 2067: 2064: 2061: 2039: 2035: 2014: 2010: 2004: 2000: 1996: 1993: 1990: 1984: 1981: 1978: 1971: 1967: 1962: 1957: 1953: 1930: 1926: 1916: 1902: 1880: 1876: 1855: 1835: 1829: 1826: 1823: 1813: 1812:ordered pairs 1797: 1793: 1787: 1783: 1779: 1776: 1773: 1767: 1764: 1761: 1754: 1748: 1745: 1742: 1738: 1734: 1729: 1725: 1719: 1716: 1713: 1709: 1700: 1684: 1681: 1673: 1656: 1652: 1649: 1646: 1643: 1638: 1634: 1629: 1616: 1614: 1601: 1592: 1589: 1586: 1580: 1574: 1571: 1568: 1562: 1556: 1553: 1550: 1544: 1538: 1535: 1532: 1526: 1520: 1517: 1514: 1505: 1500: 1495: 1491: 1487: 1482: 1477: 1473: 1469: 1464: 1460: 1456: 1451: 1447: 1424: 1420: 1416: 1411: 1407: 1386: 1381: 1377: 1353: 1350: 1347: 1324: 1315: 1298: 1289: 1286: 1283: 1277: 1271: 1268: 1265: 1256: 1254: 1247: 1242: 1238: 1224: 1221: 1218: 1212: 1206: 1203: 1200: 1194: 1188: 1185: 1182: 1173: 1171: 1164: 1159: 1155: 1130: 1124: 1121: 1118: 1112: 1107: 1103: 1079: 1076: 1073: 1070: 1067: 1061: 1056: 1052: 1039: 1037: 1024: 1018: 1015: 1012: 1003: 983: 975: 971: 950: 945: 941: 937: 934: 911: 908: 905: 895: 894:ordered pairs 879: 870: 854: 850: 846: 841: 838: 835: 828: 820: 795: 791: 785: 782: 779: 775: 754: 751: 745: 737: 732: 712: 709: 706: 686: 683: 680: 672: 656: 636: 627: 611: 607: 601: 598: 595: 591: 582: 578: 574: 570: 566: 561: 559: 555: 539: 519: 511: 507: 491: 488: 466: 462: 453: 437: 432: 428: 422: 419: 416: 412: 391: 388: 365: 362: 359: 356: 351: 347: 335: 330: 327: 321: 315: 309: 303: 297: 280: 277: 274: 266: 262: 258: 236: 230: 226: 222: 219: 216: 210: 207: 204: 197: 191: 188: 185: 181: 177: 172: 168: 162: 159: 156: 152: 144: 140: 137: 134: 130: 127: 126:Set operation 124: 120: 116: 111: 99: 96: 88: 78: 74: 68: 67: 61: 57: 53: 48: 39: 38: 33: 26: 22: 3416:Georg Cantor 3411:Paul Bernays 3342:Morse–Kelley 3317: 3250: 3249:Subset  3196:hereditarily 3158:Venn diagram 3116:ordered pair 3031:Intersection 3020: 2975:Axiom schema 2813: 2784: 2758:Tagged union 2704:Direct limit 2685: 2640: 2636: 2625: 2500: 2493: 2467: 2383: 2203: 1917: 1895:the element 1698: 1620: 1316: 1043: 871: 628: 562: 331: 325: 319: 313: 307: 301: 295: 293:of the sets 264: 260: 254: 91: 85:January 2022 82: 71:Please help 63: 21:Tagged union 3441:Thomas Jech 3284:Alternative 3263:Uncountable 3217:Ultrafilter 3076:Cardinality 2980:replacement 2928:Determinacy 2781:Lang, Serge 2455:cardinality 1915:came from. 257:mathematics 77:introducing 3481:Categories 3436:Kurt Gödel 3421:Paul Cohen 3258:Transitive 3026:Identities 3010:Complement 2997:Operations 2958:Regularity 2896:Adjunction 2855:Set theory 2774:References 2684:to denote 2201:are not. 927:such that 136:Set theory 3369:Paradoxes 3289:Axiomatic 3268:Universal 3244:Singleton 3239:Recursive 3182:Countable 3177:Amorphous 3036:Power set 2953:Power set 2911:dependent 2906:countable 2815:MathWorld 2698:Coproduct 2686:coproduct 2669:⨆ 2649:∐ 2632:coproduct 2597:∈ 2586:∗ 2582:⋃ 2523:∗ 2495:Coproduct 2474:coproduct 2400:∈ 2393:∑ 2364:× 2340:∈ 2333:⨆ 2262:∈ 2251:for each 2133:∗ 2101:∗ 2083:the sets 2065:≠ 1997:∈ 1963:∗ 1780:∈ 1746:∈ 1739:⋃ 1717:∈ 1710:⨆ 1650:∈ 1501:∗ 1488:∪ 1483:∗ 1457:⊔ 1417:⊔ 1248:∗ 1165:∗ 1007:↦ 981:→ 938:∈ 847:⁡ 839:∈ 829:⋅ 821:⋃ 783:∈ 776:⨄ 752:⁡ 746:⋅ 738:∪ 710:⊎ 684:⊔ 599:∈ 592:∐ 581:bijection 569:coproduct 556:is their 510:partition 452:injection 420:∈ 413:⨆ 381:is a set 363:∈ 278:⊔ 223:∈ 189:∈ 182:⋃ 160:∈ 153:⨆ 3373:Problems 3277:Theories 3253:Superset 3229:Infinite 3058:Concepts 2938:Infinity 2862:Overview 2783:(2004), 2743:Sum type 2692:See also 454:of each 450:with an 336:of sets 3311:General 3306:Zermelo 3212:subbase 3194: ( 3133:Forcing 3111:Element 3083: ( 3061:Methods 2948:Pairing 2785:Algebra 2488:of the 2476:in the 1040:Example 571:of the 73:improve 3202:Filter 3192:Finite 3128:Family 3071:Almost 2916:global 2901:Choice 2888:Axioms 2795:  1670:be an 506:images 259:, the 3294:Naive 3224:Fuzzy 3187:Empty 3170:types 3121:tuple 3091:Class 3085:large 3046:Union 2963:Union 1848:Here 577:up to 558:union 481:into 132:Field 58:, or 3207:base 2793:ISBN 2539:copy 2304:and 2174:and 2115:and 1697:The 1095:and 869:). 649:and 323:and 311:and 299:and 263:(or 122:Type 3168:Set 2626:In 2541:of 2459:sum 2284:of 1337:in 996:as 810:or 725:or 673:as 563:In 512:of 255:In 3483:: 2812:. 2787:, 2688:. 2324:: 579:a 560:. 267:) 62:, 54:, 3251:· 3235:) 3231:( 3198:) 3087:) 2847:e 2840:t 2833:v 2818:. 2672:, 2606:A 2600:C 2594:A 2554:i 2550:A 2518:i 2514:A 2441:B 2438:+ 2435:A 2413:i 2409:A 2403:I 2397:i 2370:. 2367:I 2361:A 2358:= 2353:i 2349:A 2343:I 2337:i 2312:I 2292:A 2268:, 2265:I 2259:i 2239:A 2217:i 2213:A 2187:j 2183:A 2160:i 2156:A 2128:j 2124:A 2096:i 2092:A 2071:, 2068:j 2062:i 2040:i 2036:A 2015:. 2011:} 2005:i 2001:A 1994:x 1991:: 1988:) 1985:i 1982:, 1979:x 1976:( 1972:{ 1968:= 1958:i 1954:A 1931:i 1927:A 1903:x 1881:i 1877:A 1856:i 1836:. 1833:) 1830:i 1827:, 1824:x 1821:( 1798:. 1794:} 1788:i 1784:A 1777:x 1774:: 1771:) 1768:i 1765:, 1762:x 1759:( 1755:{ 1749:I 1743:i 1735:= 1730:i 1726:A 1720:I 1714:i 1685:. 1682:I 1657:) 1653:I 1647:i 1644:: 1639:i 1635:A 1630:( 1602:. 1599:} 1596:) 1593:1 1590:, 1587:6 1584:( 1581:, 1578:) 1575:1 1572:, 1569:5 1566:( 1563:, 1560:) 1557:0 1554:, 1551:7 1548:( 1545:, 1542:) 1539:0 1536:, 1533:6 1530:( 1527:, 1524:) 1521:0 1518:, 1515:5 1512:( 1509:{ 1506:= 1496:1 1492:A 1478:0 1474:A 1470:= 1465:1 1461:A 1452:0 1448:A 1425:1 1421:A 1412:0 1408:A 1387:, 1382:0 1378:A 1357:) 1354:0 1351:, 1348:5 1345:( 1325:0 1299:, 1296:} 1293:) 1290:1 1287:, 1284:6 1281:( 1278:, 1275:) 1272:1 1269:, 1266:5 1263:( 1260:{ 1257:= 1243:1 1239:A 1231:} 1228:) 1225:0 1222:, 1219:7 1216:( 1213:, 1210:) 1207:0 1204:, 1201:6 1198:( 1195:, 1192:) 1189:0 1186:, 1183:5 1180:( 1177:{ 1174:= 1160:0 1156:A 1131:. 1128:} 1125:6 1122:, 1119:5 1116:{ 1113:= 1108:1 1104:A 1083:} 1080:7 1077:, 1074:6 1071:, 1068:5 1065:{ 1062:= 1057:0 1053:A 1025:. 1022:) 1019:i 1016:, 1013:x 1010:( 1004:x 984:A 976:i 972:A 951:, 946:i 942:A 935:x 915:) 912:i 909:, 906:x 903:( 880:A 855:i 851:A 842:I 836:i 796:i 792:A 786:I 780:i 755:B 733:A 713:B 707:A 687:B 681:A 657:B 637:A 612:i 608:A 602:I 596:i 540:A 520:A 492:, 489:A 467:i 463:A 438:, 433:i 429:A 423:I 417:i 392:, 389:A 369:) 366:I 360:i 357:: 352:i 348:A 344:( 326:B 320:A 314:B 308:A 302:B 296:A 281:B 275:A 237:} 231:i 227:A 220:x 217:: 214:) 211:i 208:, 205:x 202:( 198:{ 192:I 186:i 178:= 173:i 169:A 163:I 157:i 98:) 92:( 87:) 83:( 69:. 34:. 27:.

Index

Tagged union
disjoint union of graphs
Disjunctive union
list of references
related reading
external links
inline citations
improve
introducing
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Set operation
Set theory
mathematics
indexed family
injection
images
partition
pairwise disjoint sets
union
category theory
coproduct
category of sets
up to
bijection
infix notation
ordered pairs
indexed family
ordered pairs
Cartesian product

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