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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.
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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
2644: 2057: 3325: 3295: 3239: 3159: 3139: 3117: 2254: 1816: 1607:{\displaystyle A_{0}\sqcup A_{1}=A_{0}^{*}\cup A_{1}^{*}=\{(5,0),(6,0),(7,0),(5,1),(6,1)\}.} 1372: 3399: 3389: 3223: 3154: 3107: 3047: 2927: 2751: 2544: 2207: 2177: 2150: 2030: 1921: 1871: 1340: 898: 457: 1803:{\displaystyle \bigsqcup _{i\in I}A_{i}=\bigcup _{i\in I}\left\{(x,i):x\in A_{i}\right\}.} 8: 3394: 3305: 3213: 3208: 3022: 2964: 2895: 2831: 2430: 505: 243:{\displaystyle \bigsqcup _{i\in I}A_{i}=\bigcup _{i\in I}\left\{(x,i):x\in A_{i}\right\}} 1677: 484: 384: 3317: 3312: 3097: 3052: 2959: 2736: 2481: 2307: 2287: 2234: 1898: 1851: 1320: 875: 652: 632: 557: 535: 515: 451: 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
3174: 3011: 2974: 2944: 2868: 2806: 2792: 2502: 2489: 2462: 2281: 135: 31: 3462: 3452: 3437: 3432: 3300: 2954: 2809: 2485: 2477: 572: 3331: 3269: 3087: 2900: 2627: 2505:, the indexed family can be treated simply as a collection of sets. In this case 2469: 564: 3467: 3264: 3245: 3149: 3134: 3091: 2969: 1671: 670: 333: 3487: 3472: 3274: 3188: 3183: 1811: 3442: 3422: 3417: 3235: 3164: 3122: 2981: 2878: 2757: 2703: 893: 114: 20: 3447: 3082: 2454: 552:
belongs to exactly one of these images). A disjoint union of a family of
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is used for the disjoint union of a family of sets, or the notation
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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 2804: 2768:
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816: 773: 589: 410: 2667: 2647: 2574: 2547: 2511: 2433: 2390: 2330: 2310: 2290: 2257: 2237: 2210: 2180: 2153: 2121: 2089: 2060: 2033: 1951: 1924: 1901: 1874: 1854: 1819: 1707: 1680: 1627: 1445: 1405: 1375: 1343: 1323: 1149: 1101: 1050: 1002: 969: 933: 901: 878: 731: 705: 679: 655: 635: 538: 518: 487: 460: 387: 342: 273: 150: 2739: â€“ Mathematical ways to group elements of a set 2714:
Pages displaying wikidata descriptions as a fallback
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is canonically embedded in the disjoint union. For
2375:{\displaystyle \bigsqcup _{i\in I}A_{i}=A\times I.} 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: 3485: 2621: 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 1598: 1508: 1295: 1259: 1230: 1176: 1127: 1115: 1082: 1064: 2754: â€“ Elements in exactly one of two sets 2733: â€“ Equalities for combinations of sets 2846: 2832: 113: 2579: 2578: 1663:{\displaystyle \left(A_{i}:i\in I\right)} 832: 749: 95:Learn how and when to remove this message 2480:. It therefore satisfies the associated 1616: 2700: â€“ Category-theoretic construction 1810:The elements of the disjoint union are 305:is the set formed from the elements of 3486: 2204:In the extreme case where each of the 443:{\textstyle \bigsqcup _{i\in I}A_{i},} 2827: 2805: 1945:is canonically isomorphic to the set 803:{\textstyle \biguplus _{i\in I}A_{i}} 2779: 2731:List of set identities and relations 36: 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 13: 14: 3510: 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 2853: 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 2773: 2622:Category theory point of view 2457:of the disjoint union is the 3494:Basic concepts in set theory 2472:, the disjoint union is the 567:, the disjoint union is the 7: 2691: 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 10: 3515: 3344: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 1039: 989:{\displaystyle A_{i}\to A} 532:(that is, each element of 29: 18: 3408: 3371: 3283: 3173: 3145:One-to-one correspondence 3061: 3002: 2886: 2875: 2861: 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} 141: 131: 121: 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. 3103: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: 3326:Principia Mathematica 3160:Transfinite induction 3019:(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: 3400:Burali-Forti paradox 3155:Set-builder notation 3108:Continuum hypothesis 3048: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: 3361: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: 3499:Operations on sets 2950: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 107: 52:list of references 3481: 3480: 3390:Russell's paradox 3339:Zermelo–Fraenkel 3240:Dedekind-infinite 3113:Diagonal argument 3012: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 3506: 3463:Bertrand Russell 3453:John von Neumann 3438:Abraham Fraenkel 3433:Richard Dedekind 3395:Suslin's problem 3306:Cantor's theorem 3023:De Morgan's laws 2881: 2848: 2841: 2834: 2825: 2824: 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: 106: 100: 93: 89: 86: 80: 75:this article by 66:inline citations 45: 44: 37: 3514: 3513: 3509: 3508: 3507: 3505: 3504: 3503: 3484: 3483: 3482: 3477: 3404: 3383: 3367: 3332:New Foundations 3279: 3169: 3088:Cardinal number 3071: 3057: 2998: 2882: 2873: 2857: 2852: 2799: 2776: 2767: 2746: 2713: 2694: 2666: 2663: 2662: 2646: 2643: 2642: 2628:category theory 2624: 2592: 2584: 2580: 2577: 2575: 2573: 2570: 2569: 2552: 2548: 2546: 2543: 2542: 2521: 2516: 2510: 2507: 2506: 2470:category theory 2432: 2429: 2428: 2411: 2407: 2395: 2389: 2386: 2385: 2351: 2347: 2335: 2329: 2326: 2325: 2309: 2306: 2305: 2289: 2286: 2285: 2256: 2253: 2252: 2236: 2233: 2232: 2215: 2211: 2209: 2206: 2205: 2185: 2181: 2179: 2176: 2175: 2158: 2154: 2152: 2149: 2148: 2131: 2126: 2120: 2117: 2116: 2099: 2094: 2088: 2085: 2084: 2059: 2056: 2055: 2038: 2034: 2032: 2029: 2028: 2003: 1999: 1974: 1970: 1961: 1956: 1950: 1947: 1946: 1929: 1925: 1923: 1920: 1919: 1900: 1897: 1896: 1879: 1875: 1873: 1870: 1869: 1853: 1850: 1849: 1818: 1815: 1814: 1786: 1782: 1757: 1753: 1741: 1728: 1724: 1712: 1706: 1703: 1702: 1679: 1676: 1675: 1637: 1633: 1632: 1628: 1626: 1623: 1622: 1619: 1499: 1494: 1481: 1476: 1463: 1459: 1450: 1446: 1444: 1441: 1440: 1423: 1419: 1410: 1406: 1404: 1401: 1400: 1380: 1376: 1374: 1371: 1370: 1342: 1339: 1338: 1322: 1319: 1318: 1302: 1301: 1252: 1246: 1241: 1234: 1233: 1169: 1163: 1158: 1150: 1148: 1145: 1144: 1106: 1102: 1100: 1097: 1096: 1055: 1051: 1049: 1046: 1045: 1042: 1001: 998: 997: 974: 970: 968: 965: 964: 944: 940: 932: 929: 928: 900: 897: 896: 877: 874: 873: 853: 849: 834: 827: 819: 818: 817: 815: 812: 811: 794: 790: 778: 772: 769: 768: 744: 736: 735: 730: 727: 726: 704: 701: 700: 678: 675: 674: 654: 651: 650: 634: 631: 630: 626:is often used. 610: 606: 594: 588: 585: 584: 565:category theory 537: 534: 533: 517: 514: 513: 486: 483: 482: 465: 461: 459: 456: 455: 431: 427: 415: 409: 406: 405: 386: 383: 382: 350: 346: 341: 338: 337: 324: 318: 312: 306: 300: 294: 272: 269: 268: 229: 225: 200: 196: 184: 171: 167: 155: 149: 146: 145: 101: 90: 84: 81: 70: 56:related reading 46: 42: 35: 28: 17: 12: 11: 5: 3512: 3502: 3501: 3496: 3479: 3478: 3476: 3475: 3470: 3468:Thoralf Skolem 3465: 3460: 3455: 3450: 3445: 3440: 3435: 3430: 3425: 3420: 3414: 3412: 3406: 3405: 3403: 3402: 3397: 3392: 3386: 3384: 3382: 3381: 3378: 3372: 3369: 3368: 3366: 3365: 3364: 3363: 3358: 3353: 3352: 3351: 3336: 3335: 3334: 3322: 3321: 3320: 3309: 3308: 3303: 3298: 3293: 3287: 3285: 3281: 3280: 3278: 3277: 3272: 3267: 3262: 3253: 3248: 3243: 3233: 3228: 3227: 3226: 3221: 3216: 3206: 3196: 3191: 3186: 3180: 3178: 3171: 3170: 3168: 3167: 3162: 3157: 3152: 3150:Ordinal number 3147: 3142: 3137: 3132: 3131: 3130: 3125: 3115: 3110: 3105: 3100: 3095: 3085: 3080: 3074: 3072: 3070: 3069: 3066: 3062: 3059: 3058: 3056: 3055: 3050: 3045: 3040: 3035: 3030: 3028:Disjoint union 3025: 3020: 3014: 3008: 3006: 3000: 2999: 2997: 2996: 2995: 2994: 2989: 2978: 2977: 2975:Martin's axiom 2972: 2967: 2962: 2957: 2952: 2947: 2942: 2940:Extensionality 2937: 2936: 2935: 2925: 2920: 2919: 2918: 2913: 2908: 2898: 2892: 2890: 2884: 2883: 2876: 2874: 2872: 2871: 2865: 2863: 2859: 2858: 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: 9: 6: 4: 3: 2: 3511: 3500: 3497: 3495: 3492: 3491: 3489: 3474: 3473:Ernst Zermelo 3471: 3469: 3466: 3464: 3461: 3459: 3458:Willard Quine 3456: 3454: 3451: 3449: 3446: 3444: 3441: 3439: 3436: 3434: 3431: 3429: 3426: 3424: 3421: 3419: 3416: 3415: 3413: 3411: 3410:Set theorists 3407: 3401: 3398: 3396: 3393: 3391: 3388: 3387: 3385: 3379: 3377: 3374: 3373: 3370: 3362: 3359: 3357: 3356:Kripke–Platek 3354: 3350: 3347: 3346: 3345: 3342: 3341: 3340: 3337: 3333: 3330: 3329: 3328: 3327: 3323: 3319: 3316: 3315: 3314: 3311: 3310: 3307: 3304: 3302: 3299: 3297: 3294: 3292: 3289: 3288: 3286: 3282: 3276: 3273: 3271: 3268: 3266: 3263: 3261: 3259: 3254: 3252: 3249: 3247: 3244: 3241: 3237: 3234: 3232: 3229: 3225: 3222: 3220: 3217: 3215: 3212: 3211: 3210: 3207: 3204: 3200: 3197: 3195: 3192: 3190: 3187: 3185: 3182: 3181: 3179: 3176: 3172: 3166: 3163: 3161: 3158: 3156: 3153: 3151: 3148: 3146: 3143: 3141: 3138: 3136: 3133: 3129: 3126: 3124: 3121: 3120: 3119: 3116: 3114: 3111: 3109: 3106: 3104: 3101: 3099: 3096: 3093: 3089: 3086: 3084: 3081: 3079: 3076: 3075: 3073: 3067: 3064: 3063: 3060: 3054: 3051: 3049: 3046: 3044: 3041: 3039: 3036: 3034: 3031: 3029: 3026: 3024: 3021: 3018: 3015: 3013: 3010: 3009: 3007: 3005: 3001: 2993: 2992:specification 2990: 2988: 2985: 2984: 2983: 2980: 2979: 2976: 2973: 2971: 2968: 2966: 2963: 2961: 2958: 2956: 2953: 2951: 2948: 2946: 2943: 2941: 2938: 2934: 2931: 2930: 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: 2765: 2762: 2759: 2756: 2753: 2750: 2744: 2741: 2738: 2735: 2732: 2729: 2726: 2723: 2720: 2717: 2711: 2708: 2705: 2702: 2699: 2696: 2695: 2689: 2687: 2671: 2668: 2648: 2639: 2635: 2633: 2629: 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: 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: 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: 3423:Georg Cantor 3418:Paul Bernays 3349:Morse–Kelley 3324: 3257: 3256:Subset  3203:hereditarily 3165:Venn diagram 3123:ordered pair 3038:Intersection 3027: 2982: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 3448:Thomas Jech 3291:Alternative 3270:Uncountable 3224:Ultrafilter 3083:Cardinality 2987:replacement 2928:Determinacy 2781:Lang, Serge 2455:cardinality 1915:came from. 257:mathematics 77:introducing 3488:Categories 3443:Kurt Gödel 3428:Paul Cohen 3265:Transitive 3033:Identities 3017:Complement 3004:Operations 2965:Regularity 2933:projective 2896:Adjunction 2855:Set theory 2774:References 2684:to denote 2201:are not. 927:such that 136:Set theory 3376:Paradoxes 3296:Axiomatic 3275:Universal 3251:Singleton 3246:Recursive 3189:Countable 3184:Amorphous 3043:Power set 2960: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:⨆ 3380:Problems 3284:Theories 3260:Superset 3236:Infinite 3065:Concepts 2945:Infinity 2862:Overview 2783:(2004), 2743:Sum type 2692:See also 454:of each 450:with an 336:of sets 3318:General 3313:Zermelo 3219:subbase 3201: ( 3140:Forcing 3118:Element 3090: ( 3068:Methods 2955:Pairing 2785:Algebra 2488:of the 2476:in the 1040:Example 571:of the 73:improve 3209:Filter 3199:Finite 3135:Family 3078:Almost 2916:global 2901:Choice 2888:Axioms 2795:  1670:be an 506:images 259:, the 3301:Naive 3231:Fuzzy 3194:Empty 3177:types 3128:tuple 3098:Class 3092:large 3053:Union 2970:Union 1848:Here 577:up to 558:union 481:into 132:Field 58:, or 3214: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 3175: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 3490:: 2812:. 2787:, 2688:. 2324:: 579:a 560:. 267:) 62:, 54:, 3258:· 3242:) 3238:( 3205:) 3094:) 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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