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Coproduct

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4608: 4855: 4875: 4865: 1405: 802: 1692:, coproducts in other categories are not all obviously based on the notion for sets, because unions don't behave well with respect to preserving operations (e.g. the union of two groups need not be a group), and so coproducts in different categories can be dramatically different from each other. For example, the coproduct in the 2972: 1788:
The concept of disjoint union secretly underlies the above examples: the direct sum of abelian groups is the group generated by the "almost" disjoint union (disjoint union of all nonzero elements, together with a common zero), similarly for vector spaces: the space
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by the "almost" disjoint union; the free product for groups is generated by the set of all letters from a similar "almost disjoint" union where no two elements from different sets are allowed to commute. This pattern holds for any
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That it is an injection follows from the universal construction which stipulates the uniqueness of such maps. The naturality of the isomorphism is also a consequence of the diagram. Thus the contravariant
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reversed. Despite this seemingly innocuous change in the name and notation, coproducts can be and typically are dramatically different from products within a given category.
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exist, then it is possible to choose the products in a compatible fashion so that the coproduct turns into a functor
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many nonzero terms. (It therefore coincides exactly with the direct product in the case of finitely many factors.)
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This article is about coproducts in categories. For "coproduct" in the sense of comultiplication, see
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changes coproducts into products. Stated another way, the hom-functor, viewed as a functor from the
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will have a coproduct in general, but if it does, then the coproduct is unique in a strong sense: if
78: 3758: 3189:{\displaystyle \coprod _{j\in J}f_{j}\in \operatorname {Hom} \left(\coprod _{j\in J}X_{j},Y\right).} 4659: 4607: 4537: 4533: 4337: 3546: 2843: 1372: 1064: 795: 70: 915: 356: 4513: 4508: 4490: 4372: 4347: 2180: 1829: 1693: 1069: 529: 2457: 4822: 4759: 4747: 4649: 4574: 4569: 4527: 4523: 4305: 4300: 4192: 4174: 4029: 3726: 3290: 3093: 1869: 1758: 1743: 1560: 1293: 58: 2401: 4783: 4669: 4644: 4579: 4564: 4559: 4498: 4327: 4295: 4202: 3089: 2222: 2153: 1724: 1668: 1378: 958: 240: 2676: 1817:
sum, which cannot be so easily conceptualized as an "almost disjoint" sum, but does have a
1785:(which amounts to joining a collection of spaces with base points at a common base point). 1635: 1038: 1011: 213: 163: 136: 4695: 4261: 4206: 4188: 3802: 1778: 42: 4732: 2355: 1086: 190: 4727: 4711: 4674: 4664: 4584: 4058: 4038: 3846: 3784: 3738: 3538: 3376: 3326: 3206: 2825: 2801: 2781: 2761: 2541: 2521: 2498: 2492: 2381: 2228: 1894: 1874: 1847: 1825: 1689: 1673: 1414: 1227: 1158: 1080: 811: 535: 112: 54: 34:. For additional substances that result from the manufacturing of another product, see 4893: 4722: 4554: 4431: 4357: 2702: 1802: 1774: 1707: 1685: 4476: 4377: 4136: 4017: 3624:{\displaystyle X\oplus (Y\oplus Z)\cong (X\oplus Y)\oplus Z\cong X\oplus Y\oplus Z} 2246: 1698: 1073: 82: 66: 4737: 4223:
which generates examples of coproducts in the category of finite sets. Written by
4717: 4589: 4459: 4131: 4013: 4002: 3733: 3286: 3074:{\displaystyle (f_{j})_{j\in J}\in \prod _{j\in J}\operatorname {Hom} (X_{j},Y)} 2070: 1790: 4024:, this morphism is an isomorphism and the corresponding object is known as the 4769: 4707: 4320: 3394: 3200: 1717: 1712: 74: 35: 4763: 4025: 2978: 2484: 1818: 1806: 1782: 31: 1404: 801: 17: 4832: 4464: 4362: 1810: 1766: 1176: 98: 86: 4802: 4792: 4441: 4352: 2819: 1865: 1841: 1840:
The coproduct construction given above is actually a special case of a
97:, which means the definition is the same as the product but with all 4797: 3722: 1765:. That is, it is a disjoint union of the underlying sets, and the 4679: 4230: 3537:, coproduct functors have been chosen as above, and 0 denotes the 2982: 3725:; a category with finite coproducts is an example of a symmetric 1716:, consists of the elements of the direct product which have only 3721:
These properties are formally similar to those of a commutative
4619: 4272: 4234: 2183:, the coproduct can be understood as a universal morphism. Let 2069:, then (by the definition of coproducts) there exists a unique 1821:
almost-disjointly generated by the unit ball is the cofactors.
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The definition of a coproduct can be extended to an arbitrary
4158:"Banach spaces (and Lawvere metrics, and closed categories)" 3203:
follows from the commutativity of the diagram: any morphism
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is a set such that all coproducts for families indexed with
1403: 800: 1750:, the coproduct is a quotient of the tensor algebra (see 2751:{\displaystyle \operatorname {Hom} _{C}\left(U,V\right)} 4028:. A category with all finite biproducts is known as a 3895:
as in the preceding paragraph. We thus have morphisms
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We then have 3323:is continuous; it preserves limits (a coproduct in 53:, is a construction which includes as examples the 4100: 4067: 4047: 3989: 3951: 3919: 3887: 3855: 3835: 3793: 3773: 3747: 3710: 3668: 3623: 3525: 3479: 3433: 3385: 3362: 3335: 3311: 3273: 3215: 3188: 3073: 2966: 2834: 2810: 2790: 2770: 2750: 2692: 2662: 2616: 2583: 2550: 2530: 2507: 2472: 2446: 2410: 2390: 2370: 2344: 2308: 2276: 2237: 2213: 2168: 2142: 2096: 2061: 2028: 1982: 1936: 1903: 1883: 1856: 1702:, is quite complicated. On the other hand, in the 1651: 1624: 1581: 1547: 1501: 1458: 1423: 1393: 1363: 1314: 1282: 1236: 1216: 1167: 1147: 1098: 1054: 1027: 1000: 947: 905: 863: 820: 786: 737: 691: 639: 590: 544: 520: 454: 388: 345: 302: 259: 229: 202: 179: 152: 121: 3863:is also initial, we have a canonical isomorphism 3096:, so it is a tuple of morphisms) to the morphism 1773:, in a rather evident sense. In the category of 4108:. Note that, like the product, this functor is 2398:is given by a universal morphism to the functor 1844:in category theory. The coproduct in a category 521:{\displaystyle i_{2}:X_{2}\to X_{1}\sqcup X_{2}} 455:{\displaystyle i_{1}:X_{1}\to X_{1}\sqcup X_{2}} 3669:{\displaystyle X\oplus 0\cong 0\oplus X\cong X} 3526:{\displaystyle X_{1}\oplus \ldots \oplus X_{n}} 3990:{\displaystyle X\oplus Y\rightarrow X\times Y} 3836:{\displaystyle X\oplus Y\rightarrow Z\oplus Y} 2214:{\displaystyle \Delta :C\rightarrow C\times C} 4246: 3434:{\displaystyle J=\lbrace 1,\ldots ,n\rbrace } 1632:to indicate its dependence on the individual 8: 4187:. Vol. 5 (2nd ed.). New York, NY: 3428: 3410: 2611: 2598: 2056: 2043: 1931: 1918: 1761:, coproducts are disjoint unions with their 1148:{\displaystyle \left\{X_{j}:j\in J\right\}} 828:making this diagram commute may be denoted 4874: 4864: 4691: 4635: 4616: 4392: 4280: 4269: 4253: 4239: 4231: 4086: 4080: 4075:, then the coproduct comprises a functor 4060: 4040: 3964: 3959:, by which we infer a canonical morphism 3932: 3900: 3868: 3848: 3810: 3786: 3760: 3740: 3711:{\displaystyle X\oplus Y\cong Y\oplus X.} 3682: 3637: 3556: 3533:. Suppose all finite coproducts exist in 3517: 3498: 3492: 3471: 3452: 3446: 3402: 3378: 3354: 3348: 3328: 3303: 3297: 3256: 3246: 3231: 3208: 3166: 3150: 3126: 3110: 3104: 3056: 3031: 3012: 3002: 2993: 2949: 2933: 2917: 2893: 2877: 2859: 2853: 2827: 2803: 2783: 2763: 2720: 2714: 2684: 2678: 2654: 2638: 2632: 2605: 2596: 2569: 2563: 2543: 2523: 2500: 2459: 2423: 2403: 2383: 2357: 2321: 2289: 2253: 2230: 2188: 2155: 2134: 2121: 2109: 2077: 2050: 2041: 2014: 2001: 1995: 1968: 1955: 1949: 1925: 1916: 1896: 1876: 1849: 1796:variety in the sense of universal algebra 1643: 1637: 1616: 1600: 1594: 1562: 1548:{\displaystyle \bigoplus _{j\in J}X_{j}.} 1536: 1520: 1514: 1493: 1477: 1471: 1446: 1436: 1416: 1380: 1352: 1333: 1327: 1295: 1268: 1255: 1249: 1229: 1202: 1189: 1183: 1160: 1122: 1111: 1088: 1046: 1040: 1019: 1013: 984: 971: 960: 936: 923: 917: 894: 881: 875: 852: 839: 833: 813: 775: 756: 750: 729: 710: 704: 677: 664: 652: 622: 609: 603: 576: 563: 557: 537: 512: 499: 486: 473: 467: 446: 433: 420: 407: 401: 377: 364: 358: 334: 321: 315: 291: 278: 272: 248: 242: 221: 215: 192: 171: 165: 144: 138: 114: 4180:Categories for the Working Mathematician 3274:{\displaystyle (f\circ i_{j})_{j\in J}.} 2029:{\displaystyle k_{j}:X_{j}\rightarrow Y} 1983:{\displaystyle i_{j}:X_{j}\rightarrow X} 692:{\displaystyle f:X_{1}\sqcup X_{2}\to Y} 4148: 3363:{\displaystyle C^{\operatorname {op} }} 3312:{\displaystyle C^{\operatorname {op} }} 4035:If all families of objects indexed by 3952:{\displaystyle X\oplus Y\rightarrow Y} 3920:{\displaystyle X\oplus Y\rightarrow X} 2663:{\displaystyle \coprod _{j\in J}X_{j}} 1625:{\displaystyle \coprod _{j\in J}f_{j}} 1502:{\displaystyle \coprod _{j\in J}X_{j}} 2758:denote the set of all morphisms from 2617:{\displaystyle \lbrace X_{j}\rbrace } 2062:{\displaystyle \lbrace X_{j}\rbrace } 1937:{\displaystyle \lbrace X_{j}\rbrace } 1864:can be defined as the colimit of any 210:An object is called the coproduct of 7: 1752:free product of associative algebras 1459:{\displaystyle \left\{X_{j}\right\}} 3480:{\displaystyle X_{1},\ldots ,X_{n}} 1364:{\displaystyle f_{j}=f\circ i_{j}.} 787:{\displaystyle f_{2}=f\circ i_{2}.} 4101:{\displaystyle C^{J}\rightarrow C} 2584:{\displaystyle C^{J}\rightarrow C} 2405: 2190: 2143:{\displaystyle f\circ i_{j}=k_{j}} 906:{\displaystyle f_{1}\oplus f_{2},} 864:{\displaystyle f_{1}\sqcup f_{2},} 738:{\displaystyle f_{1}=f\circ i_{1}} 346:{\displaystyle X_{1}\oplus X_{2},} 303:{\displaystyle X_{1}\sqcup X_{2},} 25: 3755:, then we have a unique morphism 2036:are two coproducts of the family 1801:The coproduct in the category of 640:{\displaystyle f_{2}:X_{2}\to Y,} 4873: 4863: 4854: 4853: 4606: 3888:{\displaystyle Z\oplus Y\cong Y} 3441:, then the coproduct of objects 2447:{\displaystyle \left(X,Y\right)} 2345:{\displaystyle \left(f,f\right)} 2309:{\displaystyle f:X\rightarrow Y} 2277:{\displaystyle \left(X,X\right)} 2097:{\displaystyle f:X\rightarrow Y} 1283:{\displaystyle f_{j}:X_{j}\to Y} 1244:and any collection of morphisms 1217:{\displaystyle i_{j}:X_{j}\to X} 591:{\displaystyle f_{1}:X_{1}\to Y} 89:. It is the category-theoretic 3223:is the coproduct of the tuple 1371:That is, the following diagram 1290:there exists a unique morphism 794:That is, the following diagram 647:there exists a unique morphism 27:Category-theoretic construction 4156:Qiaochu Yuan (June 23, 2012). 4092: 3975: 3943: 3911: 3821: 3774:{\displaystyle X\rightarrow Z} 3765: 3594: 3582: 3576: 3564: 3253: 3233: 3068: 3049: 3009: 2995: 2961: 2942: 2591:. The coproduct of the family 2575: 2300: 2199: 2088: 2020: 1974: 1573: 1306: 1274: 1208: 1175:together with a collection of 683: 628: 582: 492: 426: 1: 4185:Graduate Texts in Mathematics 2483:The coproduct indexed by the 2225:which assigns to each object 1744:category of (noncommutative) 1710:), the coproduct, called the 1106:The coproduct of the family 1083:of objects indexed by a set 1068:, although they need not be 948:{\displaystyle f_{1}+f_{2},} 389:{\displaystyle X_{1}+X_{2},} 4548:Constructions on categories 4916: 4655:Higher-dimensional algebra 2624:is then often denoted by 1771:open in each of the spaces 1704:category of abelian groups 1224:such that, for any object 29: 4849: 4628: 4615: 4604: 4279: 4268: 2473:{\displaystyle C\times C} 1763:disjoint union topologies 528:satisfying the following 396:if there exist morphisms 4900:Limits (category theory) 1732:category of commutative 1582:{\displaystyle f:X\to Y} 1315:{\displaystyle f:X\to Y} 4465:Cokernels and quotients 4388:Universal constructions 2411:{\displaystyle \Delta } 1781:, the coproduct is the 1730:, the coproduct in the 1557:Sometimes the morphism 4622:Higher category theory 4368:Natural transformation 4102: 4069: 4049: 3991: 3953: 3921: 3889: 3857: 3837: 3805:) and thus a morphism 3795: 3775: 3749: 3732:If the category has a 3712: 3670: 3625: 3527: 3481: 3435: 3387: 3364: 3337: 3313: 3275: 3217: 3190: 3075: 2968: 2836: 2812: 2792: 2772: 2752: 2694: 2664: 2618: 2585: 2552: 2532: 2509: 2474: 2448: 2412: 2392: 2372: 2346: 2310: 2278: 2239: 2215: 2170: 2169:{\displaystyle j\in J} 2144: 2098: 2063: 2030: 1984: 1938: 1905: 1885: 1858: 1653: 1626: 1583: 1549: 1503: 1460: 1425: 1408: 1395: 1394:{\displaystyle j\in J} 1365: 1316: 1284: 1238: 1218: 1169: 1149: 1100: 1056: 1029: 1002: 1001:{\displaystyle \left.} 949: 907: 865: 822: 805: 788: 739: 693: 641: 592: 546: 522: 456: 390: 347: 304: 261: 260:{\displaystyle X_{2},} 231: 204: 181: 154: 123: 4221:Interactive Web page 4103: 4070: 4050: 4030:semiadditive category 3992: 3954: 3922: 3890: 3858: 3838: 3796: 3776: 3750: 3713: 3671: 3626: 3528: 3482: 3436: 3388: 3365: 3338: 3314: 3276: 3218: 3191: 3076: 2969: 2837: 2813: 2793: 2773: 2753: 2695: 2693:{\displaystyle i_{j}} 2665: 2619: 2586: 2553: 2533: 2510: 2475: 2449: 2413: 2393: 2373: 2352:. Then the coproduct 2347: 2311: 2284:and to each morphism 2279: 2240: 2216: 2171: 2145: 2099: 2064: 2031: 1985: 1939: 1906: 1886: 1859: 1667:The coproduct in the 1654: 1652:{\displaystyle f_{j}} 1627: 1584: 1550: 1504: 1461: 1426: 1407: 1396: 1366: 1317: 1285: 1239: 1219: 1170: 1150: 1101: 1057: 1055:{\displaystyle i_{2}} 1030: 1028:{\displaystyle i_{1}} 1003: 950: 908: 866: 823: 804: 789: 740: 694: 642: 593: 547: 523: 457: 391: 348: 305: 262: 232: 230:{\displaystyle X_{1}} 205: 182: 180:{\displaystyle X_{2}} 155: 153:{\displaystyle X_{1}} 124: 63:of topological spaces 4491:Algebraic categories 4079: 4059: 4039: 4022:preadditive category 3963: 3931: 3899: 3867: 3847: 3809: 3785: 3759: 3739: 3681: 3636: 3555: 3547:natural isomorphisms 3491: 3487:is often denoted by 3445: 3401: 3377: 3347: 3327: 3296: 3230: 3207: 3103: 2992: 2852: 2826: 2802: 2782: 2762: 2713: 2677: 2631: 2595: 2562: 2542: 2522: 2499: 2491:) is the same as an 2458: 2422: 2402: 2382: 2356: 2320: 2288: 2252: 2229: 2187: 2154: 2108: 2076: 2040: 1994: 1948: 1915: 1895: 1875: 1848: 1636: 1593: 1561: 1513: 1470: 1435: 1415: 1379: 1326: 1294: 1248: 1228: 1182: 1159: 1110: 1087: 1065:canonical injections 1039: 1012: 959: 916: 874: 832: 812: 749: 703: 651: 602: 556: 536: 466: 400: 357: 353:or sometimes simply 314: 271: 241: 214: 191: 164: 137: 113: 4660:Homotopy hypothesis 4338:Commutative diagram 4127:Limits and colimits 4055:have coproducts in 3199:That this map is a 2844:natural isomorphism 2371:{\displaystyle X+Y} 1911:. Not every family 1824:The coproduct of a 95:categorical product 4373:Universal property 4175:Mac Lane, Saunders 4162:Annoying Precision 4098: 4065: 4045: 3987: 3949: 3917: 3885: 3853: 3833: 3791: 3771: 3745: 3708: 3666: 3621: 3523: 3477: 3431: 3383: 3360: 3333: 3309: 3271: 3213: 3186: 3161: 3121: 3071: 3042: 2964: 2928: 2888: 2832: 2808: 2788: 2768: 2748: 2703:natural injections 2690: 2660: 2649: 2614: 2581: 2548: 2528: 2505: 2470: 2444: 2408: 2388: 2368: 2342: 2306: 2274: 2235: 2211: 2181:universal property 2166: 2140: 2094: 2059: 2026: 1980: 1934: 1901: 1881: 1854: 1759:topological spaces 1694:category of groups 1649: 1622: 1611: 1579: 1545: 1531: 1499: 1488: 1456: 1421: 1409: 1391: 1361: 1312: 1280: 1234: 1214: 1165: 1145: 1099:{\displaystyle J.} 1096: 1052: 1025: 998: 945: 903: 861: 818: 806: 784: 735: 689: 637: 588: 552:and any morphisms 542: 530:universal property 518: 452: 386: 343: 300: 257: 227: 203:{\displaystyle C.} 200: 177: 150: 119: 4887: 4886: 4845: 4844: 4841: 4840: 4823:monoidal category 4778: 4777: 4650:Enriched category 4602: 4601: 4598: 4597: 4575:Quotient category 4570:Opposite category 4485: 4484: 4068:{\displaystyle C} 4048:{\displaystyle J} 4016:) it is a proper 4012:(the category of 3856:{\displaystyle Z} 3794:{\displaystyle Z} 3748:{\displaystyle Z} 3727:monoidal category 3386:{\displaystyle J} 3336:{\displaystyle C} 3291:opposite category 3216:{\displaystyle f} 3146: 3106: 3094:Cartesian product 3027: 2981:which maps every 2913: 2873: 2835:{\displaystyle C} 2811:{\displaystyle C} 2791:{\displaystyle V} 2771:{\displaystyle U} 2700:are known as the 2634: 2551:{\displaystyle J} 2531:{\displaystyle J} 2508:{\displaystyle C} 2391:{\displaystyle C} 2238:{\displaystyle X} 1904:{\displaystyle C} 1884:{\displaystyle J} 1870:discrete category 1857:{\displaystyle C} 1777:, fundamental in 1706:(and equally for 1596: 1516: 1473: 1466:is often denoted 1424:{\displaystyle X} 1237:{\displaystyle Y} 1168:{\displaystyle X} 821:{\displaystyle f} 808:The unique arrow 545:{\displaystyle Y} 532:: for any object 122:{\displaystyle C} 16:(Redirected from 4907: 4877: 4876: 4867: 4866: 4857: 4856: 4692: 4670:Simplex category 4645:Categorification 4636: 4617: 4610: 4580:Product category 4565:Kleisli category 4560:Functor category 4405:Terminal objects 4393: 4328:Adjoint functors 4281: 4270: 4255: 4248: 4241: 4232: 4210: 4166: 4165: 4153: 4107: 4105: 4104: 4099: 4091: 4090: 4074: 4072: 4071: 4066: 4054: 4052: 4051: 4046: 3996: 3994: 3993: 3988: 3958: 3956: 3955: 3950: 3926: 3924: 3923: 3918: 3894: 3892: 3891: 3886: 3862: 3860: 3859: 3854: 3842: 3840: 3839: 3834: 3800: 3798: 3797: 3792: 3780: 3778: 3777: 3772: 3754: 3752: 3751: 3746: 3717: 3715: 3714: 3709: 3675: 3673: 3672: 3667: 3630: 3628: 3627: 3622: 3532: 3530: 3529: 3524: 3522: 3521: 3503: 3502: 3486: 3484: 3483: 3478: 3476: 3475: 3457: 3456: 3440: 3438: 3437: 3432: 3392: 3390: 3389: 3384: 3369: 3367: 3366: 3361: 3359: 3358: 3343:is a product in 3342: 3340: 3339: 3334: 3318: 3316: 3315: 3310: 3308: 3307: 3280: 3278: 3277: 3272: 3267: 3266: 3251: 3250: 3222: 3220: 3219: 3214: 3195: 3193: 3192: 3187: 3182: 3178: 3171: 3170: 3160: 3131: 3130: 3120: 3090:category of sets 3080: 3078: 3077: 3072: 3061: 3060: 3041: 3023: 3022: 3007: 3006: 2973: 2971: 2970: 2965: 2954: 2953: 2938: 2937: 2927: 2909: 2905: 2898: 2897: 2887: 2864: 2863: 2841: 2839: 2838: 2833: 2817: 2815: 2814: 2809: 2797: 2795: 2794: 2789: 2777: 2775: 2774: 2769: 2757: 2755: 2754: 2749: 2747: 2743: 2725: 2724: 2699: 2697: 2696: 2691: 2689: 2688: 2669: 2667: 2666: 2661: 2659: 2658: 2648: 2623: 2621: 2620: 2615: 2610: 2609: 2590: 2588: 2587: 2582: 2574: 2573: 2557: 2555: 2554: 2549: 2537: 2535: 2534: 2529: 2514: 2512: 2511: 2506: 2479: 2477: 2476: 2471: 2453: 2451: 2450: 2445: 2443: 2439: 2418:from the object 2417: 2415: 2414: 2409: 2397: 2395: 2394: 2389: 2377: 2375: 2374: 2369: 2351: 2349: 2348: 2343: 2341: 2337: 2315: 2313: 2312: 2307: 2283: 2281: 2280: 2275: 2273: 2269: 2244: 2242: 2241: 2236: 2223:diagonal functor 2220: 2218: 2217: 2212: 2175: 2173: 2172: 2167: 2149: 2147: 2146: 2141: 2139: 2138: 2126: 2125: 2103: 2101: 2100: 2095: 2068: 2066: 2065: 2060: 2055: 2054: 2035: 2033: 2032: 2027: 2019: 2018: 2006: 2005: 1989: 1987: 1986: 1981: 1973: 1972: 1960: 1959: 1943: 1941: 1940: 1935: 1930: 1929: 1910: 1908: 1907: 1902: 1890: 1888: 1887: 1882: 1863: 1861: 1860: 1855: 1815: 1725:commutative ring 1669:category of sets 1658: 1656: 1655: 1650: 1648: 1647: 1631: 1629: 1628: 1623: 1621: 1620: 1610: 1588: 1586: 1585: 1580: 1554: 1552: 1551: 1546: 1541: 1540: 1530: 1508: 1506: 1505: 1500: 1498: 1497: 1487: 1465: 1463: 1462: 1457: 1455: 1451: 1450: 1430: 1428: 1427: 1422: 1400: 1398: 1397: 1392: 1370: 1368: 1367: 1362: 1357: 1356: 1338: 1337: 1321: 1319: 1318: 1313: 1289: 1287: 1286: 1281: 1273: 1272: 1260: 1259: 1243: 1241: 1240: 1235: 1223: 1221: 1220: 1215: 1207: 1206: 1194: 1193: 1174: 1172: 1171: 1166: 1154: 1152: 1151: 1146: 1144: 1140: 1127: 1126: 1105: 1103: 1102: 1097: 1061: 1059: 1058: 1053: 1051: 1050: 1034: 1032: 1031: 1026: 1024: 1023: 1007: 1005: 1004: 999: 994: 990: 989: 988: 976: 975: 954: 952: 951: 946: 941: 940: 928: 927: 912: 910: 909: 904: 899: 898: 886: 885: 870: 868: 867: 862: 857: 856: 844: 843: 827: 825: 824: 819: 793: 791: 790: 785: 780: 779: 761: 760: 744: 742: 741: 736: 734: 733: 715: 714: 698: 696: 695: 690: 682: 681: 669: 668: 646: 644: 643: 638: 627: 626: 614: 613: 597: 595: 594: 589: 581: 580: 568: 567: 551: 549: 548: 543: 527: 525: 524: 519: 517: 516: 504: 503: 491: 490: 478: 477: 461: 459: 458: 453: 451: 450: 438: 437: 425: 424: 412: 411: 395: 393: 392: 387: 382: 381: 369: 368: 352: 350: 349: 344: 339: 338: 326: 325: 309: 307: 306: 301: 296: 295: 283: 282: 266: 264: 263: 258: 253: 252: 236: 234: 233: 228: 226: 225: 209: 207: 206: 201: 186: 184: 183: 178: 176: 175: 159: 157: 156: 151: 149: 148: 128: 126: 125: 120: 21: 4915: 4914: 4910: 4909: 4908: 4906: 4905: 4904: 4890: 4889: 4888: 4883: 4837: 4807: 4774: 4751: 4742: 4699: 4683: 4634: 4624: 4611: 4594: 4543: 4481: 4450:Initial objects 4436: 4382: 4275: 4264: 4262:Category theory 4259: 4217: 4199: 4189:Springer-Verlag 4173: 4170: 4169: 4155: 4154: 4150: 4145: 4118: 4082: 4077: 4076: 4057: 4056: 4037: 4036: 4011: 4001:it is a proper 3961: 3960: 3929: 3928: 3897: 3896: 3865: 3864: 3845: 3844: 3807: 3806: 3783: 3782: 3757: 3756: 3737: 3736: 3679: 3678: 3634: 3633: 3553: 3552: 3513: 3494: 3489: 3488: 3467: 3448: 3443: 3442: 3399: 3398: 3375: 3374: 3350: 3345: 3344: 3325: 3324: 3299: 3294: 3293: 3252: 3242: 3228: 3227: 3205: 3204: 3162: 3145: 3141: 3122: 3101: 3100: 3092:, which is the 3052: 3008: 2998: 2990: 2989: 2945: 2929: 2889: 2872: 2868: 2855: 2850: 2849: 2824: 2823: 2800: 2799: 2780: 2779: 2760: 2759: 2733: 2729: 2716: 2711: 2710: 2680: 2675: 2674: 2650: 2629: 2628: 2601: 2593: 2592: 2565: 2560: 2559: 2540: 2539: 2520: 2519: 2497: 2496: 2489:empty coproduct 2456: 2455: 2429: 2425: 2420: 2419: 2400: 2399: 2380: 2379: 2354: 2353: 2327: 2323: 2318: 2317: 2286: 2285: 2259: 2255: 2250: 2249: 2227: 2226: 2185: 2184: 2152: 2151: 2130: 2117: 2106: 2105: 2074: 2073: 2046: 2038: 2037: 2010: 1997: 1992: 1991: 1964: 1951: 1946: 1945: 1921: 1913: 1912: 1893: 1892: 1873: 1872: 1846: 1845: 1838: 1811: 1779:homotopy theory 1757:In the case of 1690:direct products 1682: 1665: 1639: 1634: 1633: 1612: 1591: 1590: 1589:may be denoted 1559: 1558: 1532: 1511: 1510: 1489: 1468: 1467: 1442: 1438: 1433: 1432: 1413: 1412: 1377: 1376: 1348: 1329: 1324: 1323: 1292: 1291: 1264: 1251: 1246: 1245: 1226: 1225: 1198: 1185: 1180: 1179: 1157: 1156: 1118: 1117: 1113: 1108: 1107: 1085: 1084: 1042: 1037: 1036: 1015: 1010: 1009: 980: 967: 966: 962: 957: 956: 932: 919: 914: 913: 890: 877: 872: 871: 848: 835: 830: 829: 810: 809: 771: 752: 747: 746: 725: 706: 701: 700: 673: 660: 649: 648: 618: 605: 600: 599: 572: 559: 554: 553: 534: 533: 508: 495: 482: 469: 464: 463: 442: 429: 416: 403: 398: 397: 373: 360: 355: 354: 330: 317: 312: 311: 287: 274: 269: 268: 244: 239: 238: 217: 212: 211: 189: 188: 167: 162: 161: 140: 135: 134: 111: 110: 107: 51:categorical sum 43:category theory 39: 28: 23: 22: 15: 12: 11: 5: 4913: 4911: 4903: 4902: 4892: 4891: 4885: 4884: 4882: 4881: 4871: 4861: 4850: 4847: 4846: 4843: 4842: 4839: 4838: 4836: 4835: 4830: 4825: 4811: 4805: 4800: 4795: 4789: 4787: 4780: 4779: 4776: 4775: 4773: 4772: 4767: 4756: 4754: 4749: 4744: 4743: 4741: 4740: 4735: 4730: 4725: 4720: 4715: 4704: 4702: 4697: 4689: 4685: 4684: 4682: 4677: 4675:String diagram 4672: 4667: 4665:Model category 4662: 4657: 4652: 4647: 4642: 4640: 4633: 4632: 4629: 4626: 4625: 4620: 4613: 4612: 4605: 4603: 4600: 4599: 4596: 4595: 4593: 4592: 4587: 4585:Comma category 4582: 4577: 4572: 4567: 4562: 4557: 4551: 4549: 4545: 4544: 4542: 4541: 4531: 4521: 4519:Abelian groups 4516: 4511: 4506: 4501: 4495: 4493: 4487: 4486: 4483: 4482: 4480: 4479: 4474: 4469: 4468: 4467: 4457: 4452: 4446: 4444: 4438: 4437: 4435: 4434: 4429: 4424: 4423: 4422: 4412: 4407: 4401: 4399: 4390: 4384: 4383: 4381: 4380: 4375: 4370: 4365: 4360: 4355: 4350: 4345: 4340: 4335: 4330: 4325: 4324: 4323: 4318: 4313: 4308: 4303: 4298: 4287: 4285: 4277: 4276: 4273: 4266: 4265: 4260: 4258: 4257: 4250: 4243: 4235: 4229: 4228: 4216: 4215:External links 4213: 4212: 4211: 4197: 4168: 4167: 4147: 4146: 4144: 4141: 4140: 4139: 4134: 4129: 4124: 4117: 4114: 4097: 4094: 4089: 4085: 4064: 4044: 4009: 3986: 3983: 3980: 3977: 3974: 3971: 3968: 3948: 3945: 3942: 3939: 3936: 3916: 3913: 3910: 3907: 3904: 3884: 3881: 3878: 3875: 3872: 3852: 3832: 3829: 3826: 3823: 3820: 3817: 3814: 3790: 3770: 3767: 3764: 3744: 3719: 3718: 3707: 3704: 3701: 3698: 3695: 3692: 3689: 3686: 3676: 3665: 3662: 3659: 3656: 3653: 3650: 3647: 3644: 3641: 3631: 3620: 3617: 3614: 3611: 3608: 3605: 3602: 3599: 3596: 3593: 3590: 3587: 3584: 3581: 3578: 3575: 3572: 3569: 3566: 3563: 3560: 3539:initial object 3520: 3516: 3512: 3509: 3506: 3501: 3497: 3474: 3470: 3466: 3463: 3460: 3455: 3451: 3430: 3427: 3424: 3421: 3418: 3415: 3412: 3409: 3406: 3382: 3357: 3353: 3332: 3306: 3302: 3282: 3281: 3270: 3265: 3262: 3259: 3255: 3249: 3245: 3241: 3238: 3235: 3212: 3197: 3196: 3185: 3181: 3177: 3174: 3169: 3165: 3159: 3156: 3153: 3149: 3144: 3140: 3137: 3134: 3129: 3125: 3119: 3116: 3113: 3109: 3084:(a product in 3082: 3081: 3070: 3067: 3064: 3059: 3055: 3051: 3048: 3045: 3040: 3037: 3034: 3030: 3026: 3021: 3018: 3015: 3011: 3005: 3001: 2997: 2975: 2974: 2963: 2960: 2957: 2952: 2948: 2944: 2941: 2936: 2932: 2926: 2923: 2920: 2916: 2912: 2908: 2904: 2901: 2896: 2892: 2886: 2883: 2880: 2876: 2871: 2867: 2862: 2858: 2831: 2807: 2787: 2767: 2746: 2742: 2739: 2736: 2732: 2728: 2723: 2719: 2687: 2683: 2671: 2670: 2657: 2653: 2647: 2644: 2641: 2637: 2613: 2608: 2604: 2600: 2580: 2577: 2572: 2568: 2547: 2527: 2504: 2493:initial object 2469: 2466: 2463: 2442: 2438: 2435: 2432: 2428: 2407: 2387: 2367: 2364: 2361: 2340: 2336: 2333: 2330: 2326: 2305: 2302: 2299: 2296: 2293: 2272: 2268: 2265: 2262: 2258: 2234: 2210: 2207: 2204: 2201: 2198: 2195: 2192: 2165: 2162: 2159: 2137: 2133: 2129: 2124: 2120: 2116: 2113: 2093: 2090: 2087: 2084: 2081: 2058: 2053: 2049: 2045: 2025: 2022: 2017: 2013: 2009: 2004: 2000: 1979: 1976: 1971: 1967: 1963: 1958: 1954: 1933: 1928: 1924: 1920: 1900: 1880: 1853: 1837: 1834: 1830:join operation 1826:poset category 1775:pointed spaces 1740:tensor product 1686:inclusion maps 1680: 1677:with the maps 1674:disjoint union 1671:is simply the 1664: 1661: 1646: 1642: 1619: 1615: 1609: 1606: 1603: 1599: 1578: 1575: 1572: 1569: 1566: 1544: 1539: 1535: 1529: 1526: 1523: 1519: 1496: 1492: 1486: 1483: 1480: 1476: 1454: 1449: 1445: 1441: 1431:of the family 1420: 1411:The coproduct 1390: 1387: 1384: 1360: 1355: 1351: 1347: 1344: 1341: 1336: 1332: 1311: 1308: 1305: 1302: 1299: 1279: 1276: 1271: 1267: 1263: 1258: 1254: 1233: 1213: 1210: 1205: 1201: 1197: 1192: 1188: 1164: 1143: 1139: 1136: 1133: 1130: 1125: 1121: 1116: 1095: 1092: 1067: 1049: 1045: 1022: 1018: 1008:The morphisms 997: 993: 987: 983: 979: 974: 970: 965: 944: 939: 935: 931: 926: 922: 902: 897: 893: 889: 884: 880: 860: 855: 851: 847: 842: 838: 817: 783: 778: 774: 770: 767: 764: 759: 755: 732: 728: 724: 721: 718: 713: 709: 688: 685: 680: 676: 672: 667: 663: 659: 656: 636: 633: 630: 625: 621: 617: 612: 608: 587: 584: 579: 575: 571: 566: 562: 541: 515: 511: 507: 502: 498: 494: 489: 485: 481: 476: 472: 449: 445: 441: 436: 432: 428: 423: 419: 415: 410: 406: 385: 380: 376: 372: 367: 363: 342: 337: 333: 329: 324: 320: 299: 294: 290: 286: 281: 277: 256: 251: 247: 224: 220: 199: 196: 187:be objects of 174: 170: 147: 143: 118: 106: 103: 55:disjoint union 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 4912: 4901: 4898: 4897: 4895: 4880: 4872: 4870: 4862: 4860: 4852: 4851: 4848: 4834: 4831: 4829: 4826: 4824: 4820: 4816: 4812: 4810: 4808: 4801: 4799: 4796: 4794: 4791: 4790: 4788: 4785: 4781: 4771: 4768: 4765: 4761: 4758: 4757: 4755: 4753: 4745: 4739: 4736: 4734: 4731: 4729: 4726: 4724: 4723:Tetracategory 4721: 4719: 4716: 4713: 4712:pseudofunctor 4709: 4706: 4705: 4703: 4701: 4693: 4690: 4686: 4681: 4678: 4676: 4673: 4671: 4668: 4666: 4663: 4661: 4658: 4656: 4653: 4651: 4648: 4646: 4643: 4641: 4637: 4631: 4630: 4627: 4623: 4618: 4614: 4609: 4591: 4588: 4586: 4583: 4581: 4578: 4576: 4573: 4571: 4568: 4566: 4563: 4561: 4558: 4556: 4555:Free category 4553: 4552: 4550: 4546: 4539: 4538:Vector spaces 4535: 4532: 4529: 4525: 4522: 4520: 4517: 4515: 4512: 4510: 4507: 4505: 4502: 4500: 4497: 4496: 4494: 4492: 4488: 4478: 4475: 4473: 4470: 4466: 4463: 4462: 4461: 4458: 4456: 4453: 4451: 4448: 4447: 4445: 4443: 4439: 4433: 4432:Inverse limit 4430: 4428: 4425: 4421: 4418: 4417: 4416: 4413: 4411: 4408: 4406: 4403: 4402: 4400: 4398: 4394: 4391: 4389: 4385: 4379: 4376: 4374: 4371: 4369: 4366: 4364: 4361: 4359: 4358:Kan extension 4356: 4354: 4351: 4349: 4346: 4344: 4341: 4339: 4336: 4334: 4331: 4329: 4326: 4322: 4319: 4317: 4314: 4312: 4309: 4307: 4304: 4302: 4299: 4297: 4294: 4293: 4292: 4289: 4288: 4286: 4282: 4278: 4271: 4267: 4263: 4256: 4251: 4249: 4244: 4242: 4237: 4236: 4233: 4226: 4225:Jocelyn Paine 4222: 4219: 4218: 4214: 4208: 4204: 4200: 4198:0-387-98403-8 4194: 4190: 4186: 4182: 4181: 4176: 4172: 4171: 4163: 4159: 4152: 4149: 4142: 4138: 4135: 4133: 4130: 4128: 4125: 4123: 4120: 4119: 4115: 4113: 4111: 4095: 4087: 4083: 4062: 4042: 4033: 4031: 4027: 4023: 4019: 4015: 4008: 4004: 4000: 3984: 3981: 3978: 3972: 3969: 3966: 3946: 3940: 3937: 3934: 3914: 3908: 3905: 3902: 3882: 3879: 3876: 3873: 3870: 3850: 3830: 3827: 3824: 3818: 3815: 3812: 3804: 3788: 3768: 3762: 3742: 3735: 3730: 3728: 3724: 3705: 3702: 3699: 3696: 3693: 3690: 3687: 3684: 3677: 3663: 3660: 3657: 3654: 3651: 3648: 3645: 3642: 3639: 3632: 3618: 3615: 3612: 3609: 3606: 3603: 3600: 3597: 3591: 3588: 3585: 3579: 3573: 3570: 3567: 3561: 3558: 3551: 3550: 3549: 3548: 3544: 3540: 3536: 3518: 3514: 3510: 3507: 3504: 3499: 3495: 3472: 3468: 3464: 3461: 3458: 3453: 3449: 3425: 3422: 3419: 3416: 3413: 3407: 3404: 3396: 3380: 3371: 3355: 3351: 3330: 3322: 3304: 3300: 3292: 3288: 3268: 3263: 3260: 3257: 3247: 3243: 3239: 3236: 3226: 3225: 3224: 3210: 3202: 3183: 3179: 3175: 3172: 3167: 3163: 3157: 3154: 3151: 3147: 3142: 3138: 3135: 3132: 3127: 3123: 3117: 3114: 3111: 3107: 3099: 3098: 3097: 3095: 3091: 3087: 3065: 3062: 3057: 3053: 3046: 3043: 3038: 3035: 3032: 3028: 3024: 3019: 3016: 3013: 3003: 2999: 2988: 2987: 2986: 2985:of morphisms 2984: 2980: 2977:given by the 2958: 2955: 2950: 2946: 2939: 2934: 2930: 2924: 2921: 2918: 2914: 2910: 2906: 2902: 2899: 2894: 2890: 2884: 2881: 2878: 2874: 2869: 2865: 2860: 2856: 2848: 2847: 2846: 2845: 2842:), we have a 2829: 2821: 2805: 2785: 2765: 2744: 2740: 2737: 2734: 2730: 2726: 2721: 2717: 2707: 2705: 2704: 2685: 2681: 2673:and the maps 2655: 2651: 2645: 2642: 2639: 2635: 2627: 2626: 2625: 2606: 2602: 2578: 2570: 2566: 2545: 2525: 2516: 2502: 2494: 2490: 2487:(that is, an 2486: 2481: 2467: 2464: 2461: 2440: 2436: 2433: 2430: 2426: 2385: 2365: 2362: 2359: 2338: 2334: 2331: 2328: 2324: 2303: 2297: 2294: 2291: 2270: 2266: 2263: 2260: 2256: 2248: 2232: 2224: 2208: 2205: 2202: 2196: 2193: 2182: 2177: 2163: 2160: 2157: 2135: 2131: 2127: 2122: 2118: 2114: 2111: 2091: 2085: 2082: 2079: 2072: 2051: 2047: 2023: 2015: 2011: 2007: 2002: 1998: 1977: 1969: 1965: 1961: 1956: 1952: 1926: 1922: 1898: 1878: 1871: 1867: 1851: 1843: 1835: 1833: 1831: 1827: 1822: 1820: 1816: 1814: 1808: 1804: 1803:Banach spaces 1799: 1797: 1792: 1786: 1784: 1780: 1776: 1772: 1768: 1764: 1760: 1755: 1753: 1749: 1747: 1741: 1737: 1735: 1729: 1726: 1721: 1719: 1715: 1714: 1709: 1708:vector spaces 1705: 1701: 1700: 1696:, called the 1695: 1691: 1687: 1683: 1676: 1675: 1670: 1662: 1660: 1644: 1640: 1617: 1613: 1607: 1604: 1601: 1597: 1576: 1570: 1567: 1564: 1555: 1542: 1537: 1533: 1527: 1524: 1521: 1517: 1494: 1490: 1484: 1481: 1478: 1474: 1452: 1447: 1443: 1439: 1418: 1406: 1402: 1388: 1385: 1382: 1374: 1358: 1353: 1349: 1345: 1342: 1339: 1334: 1330: 1309: 1303: 1300: 1297: 1277: 1269: 1265: 1261: 1256: 1252: 1231: 1211: 1203: 1199: 1195: 1190: 1186: 1178: 1162: 1155:is an object 1141: 1137: 1134: 1131: 1128: 1123: 1119: 1114: 1093: 1090: 1082: 1077: 1075: 1071: 1066: 1063: 1047: 1043: 1020: 1016: 995: 991: 985: 981: 977: 972: 968: 963: 942: 937: 933: 929: 924: 920: 900: 895: 891: 887: 882: 878: 858: 853: 849: 845: 840: 836: 815: 803: 799: 797: 781: 776: 772: 768: 765: 762: 757: 753: 730: 726: 722: 719: 716: 711: 707: 686: 678: 674: 670: 665: 661: 657: 654: 634: 631: 623: 619: 615: 610: 606: 585: 577: 573: 569: 564: 560: 539: 531: 513: 509: 505: 500: 496: 487: 483: 479: 474: 470: 447: 443: 439: 434: 430: 421: 417: 413: 408: 404: 383: 378: 374: 370: 365: 361: 340: 335: 331: 327: 322: 318: 297: 292: 288: 284: 279: 275: 254: 249: 245: 222: 218: 197: 194: 172: 168: 145: 141: 132: 116: 104: 102: 100: 96: 92: 88: 84: 83:vector spaces 80: 76: 72: 68: 64: 60: 56: 52: 48: 44: 37: 33: 19: 4803: 4784:Categorified 4688:n-categories 4639:Key concepts 4477:Direct limit 4460:Coequalizers 4454: 4378:Yoneda lemma 4284:Key concepts 4274:Key concepts 4178: 4161: 4151: 4137:Direct limit 4109: 4034: 4018:monomorphism 4014:pointed sets 4006: 3998: 3731: 3720: 3542: 3534: 3372: 3320: 3283: 3198: 3085: 3083: 2976: 2818:(that is, a 2708: 2701: 2672: 2517: 2488: 2482: 2247:ordered pair 2179:As with any 2178: 1839: 1823: 1812: 1800: 1787: 1770: 1756: 1745: 1733: 1727: 1722: 1711: 1699:free product 1697: 1678: 1672: 1666: 1556: 1410: 1078: 807: 108: 67:free product 50: 46: 40: 4752:-categories 4728:Kan complex 4718:Tricategory 4700:-categories 4590:Subcategory 4348:Exponential 4316:Preadditive 4311:Pre-abelian 4132:Coequalizer 4003:epimorphism 3734:zero object 3287:hom-functor 2071:isomorphism 1062:are called 91:dual notion 4770:3-category 4760:2-category 4733:∞-groupoid 4708:Bicategory 4455:Coproducts 4415:Equalizers 4321:Bicategory 4207:0906.18001 4143:References 4020:. In any 3395:finite set 3201:surjection 2104:such that 1836:Discussion 1807:short maps 1713:direct sum 1684:being the 1322:such that 1070:injections 699:such that 105:Definition 75:direct sum 73:, and the 36:by-product 18:Coproducts 4819:Symmetric 4764:2-functor 4504:Relations 4427:Pullbacks 4110:covariant 4093:→ 4026:biproduct 4005:while in 3982:× 3976:→ 3970:⊕ 3944:→ 3938:⊕ 3912:→ 3906:⊕ 3880:≅ 3874:⊕ 3843:. Since 3828:⊕ 3822:→ 3816:⊕ 3766:→ 3700:⊕ 3694:≅ 3688:⊕ 3661:≅ 3655:⊕ 3649:≅ 3643:⊕ 3616:⊕ 3610:⊕ 3604:≅ 3598:⊕ 3589:⊕ 3580:≅ 3571:⊕ 3562:⊕ 3511:⊕ 3508:… 3505:⊕ 3462:… 3420:… 3261:∈ 3240:∘ 3155:∈ 3148:∐ 3139:⁡ 3133:∈ 3115:∈ 3108:∐ 3047:⁡ 3036:∈ 3029:∏ 3025:∈ 3017:∈ 2979:bijection 2940:⁡ 2922:∈ 2915:∏ 2911:≅ 2882:∈ 2875:∐ 2866:⁡ 2727:⁡ 2643:∈ 2636:∐ 2576:→ 2485:empty set 2465:× 2406:Δ 2316:the pair 2301:→ 2206:× 2200:→ 2191:Δ 2161:∈ 2150:for each 2115:∘ 2089:→ 2021:→ 1975:→ 1819:unit ball 1783:wedge sum 1769:are sets 1767:open sets 1748:-algebras 1742:. In the 1736:-algebras 1688:. Unlike 1605:∈ 1598:∐ 1574:→ 1525:∈ 1518:⨁ 1482:∈ 1475:∐ 1386:∈ 1375:for each 1346:∘ 1307:→ 1275:→ 1209:→ 1177:morphisms 1135:∈ 888:⊕ 846:⊔ 769:∘ 723:∘ 684:→ 671:⊔ 629:→ 583:→ 506:⊔ 493:→ 440:⊔ 427:→ 328:⊕ 285:⊔ 47:coproduct 32:Coalgebra 4894:Category 4879:Glossary 4859:Category 4833:n-monoid 4786:concepts 4442:Colimits 4410:Products 4363:Morphism 4306:Concrete 4301:Additive 4291:Category 4177:(1998). 4116:See also 3803:terminal 2709:Letting 1723:Given a 1718:finitely 1663:Examples 1373:commutes 1072:or even 796:commutes 267:written 133:and let 131:category 87:morphism 4869:Outline 4828:n-group 4793:2-group 4748:Strict 4738:∞-topos 4534:Modules 4472:Pushout 4420:Kernels 4353:Functor 4296:Abelian 4122:Product 3781:(since 2820:hom-set 2221:be the 1868:from a 1866:functor 1842:colimit 1828:is the 1809:is the 1791:spanned 1738:is the 93:to the 79:modules 4815:Traced 4798:2-ring 4528:Fields 4514:Groups 4509:Magmas 4397:Limits 4205:  4195:  3723:monoid 3397:, say 3088:, the 1081:family 99:arrows 71:groups 65:, the 45:, the 4809:-ring 4696:Weak 4680:Topos 4524:Rings 3393:is a 2983:tuple 1891:into 1805:with 1074:monic 129:be a 49:, or 4499:Sets 4193:ISBN 3927:and 2245:the 1990:and 1035:and 745:and 598:and 462:and 237:and 160:and 109:Let 81:and 61:and 59:sets 4343:End 4333:CCC 4203:Zbl 4007:Set 3999:Grp 3801:is 3541:of 3373:If 3370:). 3321:Set 3319:to 3136:Hom 3086:Set 3044:Hom 2931:Hom 2857:Hom 2822:in 2798:in 2778:to 2718:Hom 2518:If 2495:in 2454:in 2378:in 1754:). 1659:s. 1509:or 955:or 310:or 77:of 69:of 57:of 41:In 4896:: 4821:) 4817:)( 4201:. 4191:. 4183:. 4160:. 4112:. 4032:. 3729:. 3356:op 3305:op 2706:. 2515:. 2480:. 2176:. 1832:. 1798:. 1401:: 1076:. 798:: 4813:( 4806:n 4804:E 4766:) 4762:( 4750:n 4714:) 4710:( 4698:n 4540:) 4536:( 4530:) 4526:( 4254:e 4247:t 4240:v 4227:. 4209:. 4164:. 4096:C 4088:J 4084:C 4063:C 4043:J 4010:* 3985:Y 3979:X 3973:Y 3967:X 3947:Y 3941:Y 3935:X 3915:X 3909:Y 3903:X 3883:Y 3877:Y 3871:Z 3851:Z 3831:Y 3825:Z 3819:Y 3813:X 3789:Z 3769:Z 3763:X 3743:Z 3706:. 3703:X 3697:Y 3691:Y 3685:X 3664:X 3658:X 3652:0 3646:0 3640:X 3619:Z 3613:Y 3607:X 3601:Z 3595:) 3592:Y 3586:X 3583:( 3577:) 3574:Z 3568:Y 3565:( 3559:X 3543:C 3535:C 3519:n 3515:X 3500:1 3496:X 3473:n 3469:X 3465:, 3459:, 3454:1 3450:X 3429:} 3426:n 3423:, 3417:, 3414:1 3411:{ 3408:= 3405:J 3381:J 3352:C 3331:C 3301:C 3269:. 3264:J 3258:j 3254:) 3248:j 3244:i 3237:f 3234:( 3211:f 3184:. 3180:) 3176:Y 3173:, 3168:j 3164:X 3158:J 3152:j 3143:( 3128:j 3124:f 3118:J 3112:j 3069:) 3066:Y 3063:, 3058:j 3054:X 3050:( 3039:J 3033:j 3020:J 3014:j 3010:) 3004:j 3000:f 2996:( 2962:) 2959:Y 2956:, 2951:j 2947:X 2943:( 2935:C 2925:J 2919:j 2907:) 2903:Y 2900:, 2895:j 2891:X 2885:J 2879:j 2870:( 2861:C 2830:C 2806:C 2786:V 2766:U 2745:) 2741:V 2738:, 2735:U 2731:( 2722:C 2686:j 2682:i 2656:j 2652:X 2646:J 2640:j 2612:} 2607:j 2603:X 2599:{ 2579:C 2571:J 2567:C 2546:J 2526:J 2503:C 2468:C 2462:C 2441:) 2437:Y 2434:, 2431:X 2427:( 2386:C 2366:Y 2363:+ 2360:X 2339:) 2335:f 2332:, 2329:f 2325:( 2304:Y 2298:X 2295:: 2292:f 2271:) 2267:X 2264:, 2261:X 2257:( 2233:X 2209:C 2203:C 2197:C 2194:: 2164:J 2158:j 2136:j 2132:k 2128:= 2123:j 2119:i 2112:f 2092:Y 2086:X 2083:: 2080:f 2057:} 2052:j 2048:X 2044:{ 2024:Y 2016:j 2012:X 2008:: 2003:j 1999:k 1978:X 1970:j 1966:X 1962:: 1957:j 1953:i 1932:} 1927:j 1923:X 1919:{ 1899:C 1879:J 1852:C 1813:l 1746:R 1734:R 1728:R 1681:j 1679:i 1645:j 1641:f 1618:j 1614:f 1608:J 1602:j 1577:Y 1571:X 1568:: 1565:f 1543:. 1538:j 1534:X 1528:J 1522:j 1495:j 1491:X 1485:J 1479:j 1453:} 1448:j 1444:X 1440:{ 1419:X 1389:J 1383:j 1359:. 1354:j 1350:i 1343:f 1340:= 1335:j 1331:f 1310:Y 1304:X 1301:: 1298:f 1278:Y 1270:j 1266:X 1262:: 1257:j 1253:f 1232:Y 1212:X 1204:j 1200:X 1196:: 1191:j 1187:i 1163:X 1142:} 1138:J 1132:j 1129:: 1124:j 1120:X 1115:{ 1094:. 1091:J 1048:2 1044:i 1021:1 1017:i 996:. 992:] 986:2 982:f 978:, 973:1 969:f 964:[ 943:, 938:2 934:f 930:+ 925:1 921:f 901:, 896:2 892:f 883:1 879:f 859:, 854:2 850:f 841:1 837:f 816:f 782:. 777:2 773:i 766:f 763:= 758:2 754:f 731:1 727:i 720:f 717:= 712:1 708:f 687:Y 679:2 675:X 666:1 662:X 658:: 655:f 635:, 632:Y 624:2 620:X 616:: 611:2 607:f 586:Y 578:1 574:X 570:: 565:1 561:f 540:Y 514:2 510:X 501:1 497:X 488:2 484:X 480:: 475:2 471:i 448:2 444:X 435:1 431:X 422:1 418:X 414:: 409:1 405:i 384:, 379:2 375:X 371:+ 366:1 362:X 341:, 336:2 332:X 323:1 319:X 298:, 293:2 289:X 280:1 276:X 255:, 250:2 246:X 223:1 219:X 198:. 195:C 173:2 169:X 146:1 142:X 117:C 38:. 20:)

Index

Coproducts
Coalgebra
by-product
category theory
disjoint union
sets
of topological spaces
free product
groups
direct sum
modules
vector spaces
morphism
dual notion
categorical product
arrows
category
universal property
commutes

canonical injections
injections
monic
family
morphisms
commutes

category of sets
disjoint union
inclusion maps

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