Knowledge (XXG)

Compact object (mathematics)

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286: 1917: 1727: 171: 594: 1186: 1806: 182: 2264: 403: 1616: 1834: 1644: 1537: 658: 2423: 2467: 660:
always commutes with finite colimits since these are limits. Then, one uses a presentation of filtered colimits as a coequalizer (which is a finite colimit) of an infinite coproduct.
2339: 2054: 71: 1956: 500: 1288: 1084: 1003: 2620:, which are in particular compact. In the context of ∞-categories, dualizable and compact objects tend to be more closely linked, for example in the ∞-category of complexes of 2122: 778: 435:
The terminology is motivated by an example arising from topology mentioned below. Several authors also use a terminology which is more closely related to algebraic categories:
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is the filtered colimit of its finite-dimensional (i.e., compact) subspaces. Hence the category of vector spaces (over a fixed field) is compactly generated.
1735: 2850: 2810: 701:
Similar results hold for any category of algebraic structures given by operations on a set obeying equational laws. Such categories, called
2624:-modules, compact and dualizable objects agree. This and more general example where dualizable and compact objects agree are discussed in 2692:
Hall, Jack; Neeman, Amnon; Rydh, David (2015-12-03). "One positive and two negative results for derived categories of algebraic stacks".
806:. The link between compactness in topology and the above categorical notion of compactness is as follows: for a fixed topological space 2124:, there are no compact objects other than the zero object. This observation can be generalized to the following theorem: if the stack 281:{\displaystyle \operatorname {colim} \operatorname {Hom} _{C}(X,Y_{i})\to \operatorname {Hom} _{C}(X,\operatorname {colim} _{i}Y_{i})} 2730: 2216: 615:
is compact in Neeman's sense if and only if it is compact in the ∞-categorical sense. The reason is that in a stable ∞-category,
471:(and the filtered colimits are understood in the ∞-categorical sense, sometimes also referred to as filtered homotopy colimits). 2747:
Ben-Zvi, David; Francis, John; Nadler, David (2010), "Integral transforms and Drinfeld centers in derived algebraic geometry",
799: 362: 1912:{\displaystyle \psi \in {\underset {i\in I}{\text{colim}}}{\text{ Hom}}({\mathcal {F}}^{\bullet },\mathbb {Z} _{U_{i}})} 1958:, which is not guaranteed. Proving this requires showing that any compact object has support in some compact subset of 1722:{\displaystyle \phi \in {\text{Hom}}({\mathcal {F}}^{\bullet },{\underset {i\in I}{\text{colim}}}\mathbb {Z} _{U_{i}})} 1565: 702: 2517:
In most categories, the condition of being compact is quite strong, so that most objects are not compact. A category
2872: 2832: 1494: 618: 791: 688: 2383: 2889: 2089: 2428: 166:{\displaystyle \operatorname {Hom} _{C}(X,\cdot ):C\to \mathrm {Sets} ,Y\mapsto \operatorname {Hom} _{C}(X,Y)} 2301: 2016: 1559:, it is generally not a compactly generated category. Some evidence for this can be found by considering an 611:
admitting all filtered colimits. (This condition is widely satisfied, but not automatic.) Then an object in
589:{\displaystyle \operatorname {Hom} _{C}(X,\cdot ):C\to \mathrm {Ab} ,Y\mapsto \operatorname {Hom} _{C}(X,Y)} 2057: 1925: 32: 608: 1262: 1058: 977: 480: 2594:), there is another condition imposing some kind of finiteness, namely the condition that an object is 2095: 746: 2269: 920: 829: 2127: 2063: 1992: 1446: 1395: 1316: 2571: 680: 2836: 2782: 2756: 2693: 325: 2846: 2806: 2726: 2617: 2596: 2591: 2347: 803: 604: 2798: 2766: 2718: 1560: 1488: 1087: 1008: 741: 706: 669: 52: 2860: 2820: 2778: 2740: 1811: 1235: 599:
commutes with coproducts. The relation of this notion and the above is as follows: suppose
408: 294: 2856: 2816: 2774: 2736: 1987: 785: 1181:{\displaystyle h_{(-)}:C\to {\text{PreShv}}(C),X\mapsto h_{X}:=\operatorname {Hom} (-,X)} 464: 2546: 2520: 2492: 2472: 2194: 2174: 2151: 1961: 1801:{\displaystyle {\mathcal {F}}^{\bullet }\in {\text{Ob}}(D({\text{Sh}}(X;{\text{Ab}})))} 1621: 1542: 1426: 1375: 1351: 1296: 1215: 1195: 1038: 954: 900: 880: 860: 809: 2883: 2085: 2786: 56: 2770: 467:, provided that the above set of morphisms gets replaced by the mapping space in 2570:
Categories which are compactly generated and also admit all colimits are called
1618:(which can never be refined to a finite subcover using the non-compactness of 1345: 2722: 322:. Since elements in the filtered colimit at the left are represented by maps 2341:
is the zero object. In particular, the category is not compactly generated.
487: 2543:
if any object can be expressed as a filtered colimit of compact objects in
2802: 972: 2841: 2612:-module, so this observation can be applied. Indeed, in the category of 2604:
is compact, then any dualizable object is compact as well. For example,
698:
is a field, then compact objects are finite-dimensional vector spaces.
725:) are precisely the finitely presented models. For example: suppose 359:, the surjectivity of the above map amounts to requiring that a map 2761: 2698: 2670: 1483:
Derived category of sheaves of Abelian groups on a noncompact X
802:. Instead these are precisely the finite sets endowed with the 2013:
over positive characteristic, the unbounded derived category
2259:{\displaystyle {\overline {G}}=G\otimes _{k}{\overline {k}}} 1982:
Derived category of quasi-coherent sheaves on an Artin stack
1873: 1742: 1665: 1571: 733:) is the category of groups, and the compact objects in Mod( 2616:-modules the dualizable objects are the finitely presented 176:
commutes with filtered colimits, i.e., if the natural map
1313:
can be regarded as a full subcategory of the category
2549: 2523: 2495: 2475: 2431: 2386: 2350: 2304: 2272: 2219: 2197: 2177: 2154: 2130: 2098: 2066: 2019: 1995: 1964: 1928: 1837: 1814: 1738: 1647: 1624: 1568: 1545: 1497: 1449: 1429: 1398: 1378: 1354: 1319: 1299: 1265: 1238: 1218: 1198: 1095: 1061: 1041: 1011: 980: 957: 923: 903: 883: 863: 832: 812: 749: 621: 503: 411: 365: 328: 297: 185: 74: 2625: 398:{\displaystyle X\to \operatorname {colim} _{i}Y_{i}} 2586:with a well-behaved tensor product (more formally, 2671:"On the derived category of sheaves on a manifold" 2555: 2529: 2501: 2481: 2461: 2417: 2372: 2333: 2287: 2258: 2203: 2183: 2160: 2140: 2116: 2076: 2048: 2005: 1970: 1950: 1911: 1820: 1800: 1721: 1630: 1610: 1551: 1531: 1466: 1435: 1415: 1384: 1360: 1336: 1305: 1282: 1251: 1224: 1204: 1180: 1078: 1047: 1027: 997: 963: 940: 909: 889: 869: 849: 818: 772: 652: 588: 424: 397: 347: 310: 291:is a bijection for any filtered system of objects 280: 165: 1611:{\displaystyle {\mathcal {U}}=\{U_{i}\}_{i\in I}} 1368:. Regarded as an object of this larger category, 1035:to sets) has all colimits. The original category 444: 2871:, Annals of Mathematics Studies, vol. 148, 2831:, Annals of Mathematics Studies, vol. 170, 2060:is in general not compactly generated, even if 1978:, and then showing this subset must be empty. 897:is a compact topological space if and only if 2715:Locally presentable and accessible categories 2656: 1532:{\displaystyle D({\text{Sh}}(X;{\text{Ab}}))} 653:{\displaystyle \operatorname {Hom} _{C}(X,-)} 436: 8: 2793:Kashiwara, Masaki; Schapira, Pierre (2006), 2749:Journal of the American Mathematical Society 1593: 1579: 1392:is compact. In fact, the compact objects of 35:satisfying a certain finiteness condition. 2418:{\displaystyle \mathbb {G} _{a}\to GL_{n}} 2840: 2760: 2697: 2548: 2522: 2494: 2474: 2444: 2440: 2439: 2430: 2409: 2393: 2389: 2388: 2385: 2364: 2349: 2322: 2321: 2309: 2303: 2279: 2275: 2274: 2271: 2246: 2240: 2220: 2218: 2196: 2176: 2153: 2132: 2131: 2129: 2108: 2104: 2103: 2097: 2068: 2067: 2065: 2037: 2036: 2024: 2018: 1997: 1996: 1994: 1963: 1940: 1935: 1931: 1930: 1927: 1898: 1893: 1889: 1888: 1878: 1872: 1871: 1862: 1844: 1836: 1813: 1784: 1770: 1756: 1747: 1741: 1740: 1737: 1708: 1703: 1699: 1698: 1679: 1670: 1664: 1663: 1654: 1646: 1623: 1596: 1586: 1570: 1569: 1567: 1544: 1518: 1504: 1496: 1450: 1448: 1428: 1399: 1397: 1377: 1353: 1320: 1318: 1298: 1266: 1264: 1243: 1237: 1217: 1197: 1148: 1121: 1100: 1094: 1062: 1060: 1040: 1016: 1010: 981: 979: 956: 924: 922: 902: 882: 862: 833: 831: 811: 762: 748: 626: 620: 562: 541: 508: 502: 416: 410: 389: 376: 364: 339: 327: 302: 296: 269: 256: 234: 218: 196: 184: 139: 112: 79: 73: 2462:{\displaystyle x\in \mathbb {G} _{a}(S)} 2637: 2334:{\displaystyle D_{qc}({\mathfrak {X}})} 2049:{\displaystyle D_{qc}({\mathfrak {X}})} 2344:This theorem applies, for example, to 857:whose objects are the open subsets of 705:, can be studied systematically using 491: 475:Compactness in triangulated categories 2644: 1922:it would have to factor through some 1443:(or, more precisely, their images in 1005:(i.e., the category of functors from 877:(and inclusions as morphisms). Then, 737:) are the finitely presented groups. 7: 2713:Adámek, Jiří; Rosický, Jiří (1994), 2626:Ben-Zvi, Francis & Nadler (2010) 1951:{\displaystyle \mathbb {Z} _{U_{i}}} 1539:for a non-compact topological space 459:The same definition also applies if 2323: 2133: 2092:. In fact, for the algebraic stack 2069: 2038: 1998: 494:defines an object to be compact if 1283:{\displaystyle {\text{PreShv}}(C)} 1079:{\displaystyle {\text{PreShv}}(C)} 998:{\displaystyle {\text{PreShv}}(C)} 729:is the theory of groups. Then Mod( 545: 542: 122: 119: 116: 113: 14: 2117:{\displaystyle B\mathbb {G} _{a}} 971:is any category, the category of 773:{\displaystyle D(R-{\text{Mod}})} 721:, and the compact objects in Mod( 2563:. For example, any vector space 2298:then the only compact object in 2288:{\displaystyle \mathbb {G} _{a}} 1293:In a similar vein, any category 941:{\displaystyle {\text{Open}}(X)} 850:{\displaystyle {\text{Open}}(X)} 2141:{\displaystyle {\mathfrak {X}}} 2077:{\displaystyle {\mathfrak {X}}} 2006:{\displaystyle {\mathfrak {X}}} 1467:{\displaystyle {\text{Ind}}(C)} 1416:{\displaystyle {\text{Ind}}(C)} 1337:{\displaystyle {\text{Ind}}(C)} 672:are precisely the finite sets. 445:Kashiwara & Schapira (2006) 2717:, Cambridge University Press, 2578:Relation to dualizable objects 2513:Compactly generated categories 2456: 2450: 2399: 2328: 2318: 2043: 2033: 1906: 1867: 1795: 1792: 1789: 1775: 1767: 1761: 1716: 1659: 1526: 1523: 1509: 1501: 1461: 1455: 1410: 1404: 1331: 1325: 1277: 1271: 1175: 1163: 1141: 1132: 1126: 1118: 1107: 1101: 1073: 1067: 992: 986: 935: 929: 844: 838: 800:category of topological spaces 767: 753: 647: 635: 583: 571: 555: 538: 529: 517: 449:objects of finite presentation 369: 332: 275: 243: 227: 224: 205: 160: 148: 132: 109: 100: 88: 29:objects of finite presentation 1: 2771:10.1090/S0894-0347-10-00669-7 2509:-th column in the first row. 2266:has a subgroup isomorphic to 1491:of sheaves of Abelian groups 1423:are precisely the objects of 679:, the compact objects in the 2469:to the identity matrix plus 2251: 2225: 694:-modules. In particular, if 917:is compact as an object in 798:the compact objects in the 784:-modules are precisely the 740:The compact objects in the 668:The compact objects in the 455:Compactness in ∞-categories 443:instead of compact object. 437:Adámek & Rosický (1994) 2906: 2873:Princeton University Press 2833:Princeton University Press 2657:Adámek & Rosický (1994 2600:. If the monoidal unit in 2380:by means of the embedding 2211:of positive characteristic 792:Compact topological spaces 713:, there is a category Mod( 348:{\displaystyle X\to Y_{i}} 25:finitely presented objects 709:. For any Lawvere theory 441:finitely presented object 2723:10.1017/CBO9780511600579 2373:{\displaystyle G=GL_{n}} 2191:is defined over a field 1259:is a compact object (of 826:, there is the category 2869:Triangulated Categories 2148:has a stabilizer group 2867:Neeman, Amnon (2001), 2795:Categories and sheaves 2557: 2531: 2503: 2483: 2463: 2419: 2374: 2335: 2289: 2260: 2205: 2185: 2162: 2142: 2118: 2078: 2058:quasi-coherent sheaves 2050: 2007: 1972: 1952: 1920: 1913: 1822: 1802: 1730: 1723: 1632: 1612: 1553: 1533: 1468: 1437: 1417: 1386: 1362: 1338: 1307: 1284: 1253: 1226: 1206: 1182: 1080: 1049: 1029: 1028:{\displaystyle C^{op}} 999: 965: 942: 911: 891: 871: 851: 820: 774: 654: 590: 426: 399: 349: 312: 282: 167: 23:, also referred to as 2827:Lurie, Jacob (2009), 2803:10.1007/3-540-27950-4 2675:Documenta Mathematica 2572:accessible categories 2558: 2532: 2504: 2484: 2464: 2420: 2375: 2336: 2290: 2261: 2206: 2186: 2163: 2143: 2119: 2079: 2051: 2008: 1973: 1953: 1914: 1830: 1828:to lift to an element 1823: 1821:{\displaystyle \phi } 1808:. Then, for this map 1803: 1724: 1640: 1633: 1613: 1554: 1534: 1469: 1438: 1418: 1387: 1363: 1339: 1308: 1285: 1254: 1252:{\displaystyle h_{X}} 1227: 1207: 1183: 1081: 1050: 1030: 1000: 966: 943: 912: 892: 872: 852: 821: 775: 655: 591: 481:triangulated category 427: 425:{\displaystyle Y_{i}} 400: 350: 313: 311:{\displaystyle Y_{i}} 283: 168: 2590:is required to be a 2547: 2521: 2493: 2473: 2429: 2384: 2348: 2302: 2270: 2217: 2195: 2175: 2152: 2128: 2096: 2064: 2017: 1993: 1962: 1926: 1835: 1812: 1736: 1645: 1622: 1566: 1543: 1495: 1447: 1427: 1396: 1376: 1352: 1317: 1297: 1263: 1236: 1216: 1196: 1093: 1059: 1039: 1009: 978: 955: 921: 901: 881: 861: 830: 810: 747: 619: 501: 439:use the terminology 409: 363: 326: 295: 183: 72: 16:Mathematical concept 2829:Higher topos theory 2797:, Springer Verlag, 2540:compactly generated 31:, are objects in a 2618:projective modules 2553: 2527: 2499: 2479: 2459: 2415: 2370: 2331: 2285: 2256: 2201: 2181: 2158: 2138: 2114: 2074: 2046: 2003: 1968: 1948: 1909: 1860: 1818: 1798: 1719: 1695: 1638:) and taking a map 1628: 1608: 1549: 1529: 1464: 1433: 1413: 1382: 1358: 1334: 1303: 1280: 1249: 1222: 1202: 1178: 1076: 1045: 1025: 995: 961: 938: 907: 887: 867: 847: 816: 770: 689:finitely presented 687:are precisely the 650: 586: 422: 405:factors over some 395: 345: 308: 278: 163: 2852:978-0-691-14049-0 2812:978-3-540-27949-5 2608:is compact as an 2592:monoidal category 2556:{\displaystyle C} 2530:{\displaystyle C} 2502:{\displaystyle n} 2482:{\displaystyle x} 2254: 2228: 2204:{\displaystyle k} 2184:{\displaystyle G} 2161:{\displaystyle G} 1971:{\displaystyle X} 1865: 1848: 1845: 1787: 1773: 1759: 1683: 1680: 1657: 1631:{\displaystyle X} 1552:{\displaystyle X} 1521: 1507: 1487:In the unbounded 1453: 1436:{\displaystyle C} 1402: 1385:{\displaystyle C} 1361:{\displaystyle C} 1323: 1306:{\displaystyle C} 1269: 1225:{\displaystyle C} 1205:{\displaystyle X} 1124: 1065: 1048:{\displaystyle C} 984: 964:{\displaystyle C} 927: 910:{\displaystyle X} 890:{\displaystyle X} 870:{\displaystyle X} 836: 819:{\displaystyle X} 804:discrete topology 786:perfect complexes 765: 609:stable ∞-category 605:homotopy category 486:which admits all 53:filtered colimits 51:which admits all 2897: 2875: 2863: 2844: 2823: 2789: 2764: 2743: 2704: 2703: 2701: 2689: 2683: 2682: 2666: 2660: 2654: 2648: 2642: 2562: 2560: 2559: 2554: 2536: 2534: 2533: 2528: 2508: 2506: 2505: 2500: 2488: 2486: 2485: 2480: 2468: 2466: 2465: 2460: 2449: 2448: 2443: 2425:sending a point 2424: 2422: 2421: 2416: 2414: 2413: 2398: 2397: 2392: 2379: 2377: 2376: 2371: 2369: 2368: 2340: 2338: 2337: 2332: 2327: 2326: 2317: 2316: 2294: 2292: 2291: 2286: 2284: 2283: 2278: 2265: 2263: 2262: 2257: 2255: 2247: 2245: 2244: 2229: 2221: 2210: 2208: 2207: 2202: 2190: 2188: 2187: 2182: 2167: 2165: 2164: 2159: 2147: 2145: 2144: 2139: 2137: 2136: 2123: 2121: 2120: 2115: 2113: 2112: 2107: 2083: 2081: 2080: 2075: 2073: 2072: 2055: 2053: 2052: 2047: 2042: 2041: 2032: 2031: 2012: 2010: 2009: 2004: 2002: 2001: 1988:algebraic stacks 1977: 1975: 1974: 1969: 1957: 1955: 1954: 1949: 1947: 1946: 1945: 1944: 1934: 1918: 1916: 1915: 1910: 1905: 1904: 1903: 1902: 1892: 1883: 1882: 1877: 1876: 1866: 1863: 1861: 1859: 1846: 1827: 1825: 1824: 1819: 1807: 1805: 1804: 1799: 1788: 1785: 1774: 1771: 1760: 1757: 1752: 1751: 1746: 1745: 1728: 1726: 1725: 1720: 1715: 1714: 1713: 1712: 1702: 1696: 1694: 1681: 1675: 1674: 1669: 1668: 1658: 1655: 1637: 1635: 1634: 1629: 1617: 1615: 1614: 1609: 1607: 1606: 1591: 1590: 1575: 1574: 1558: 1556: 1555: 1550: 1538: 1536: 1535: 1530: 1522: 1519: 1508: 1505: 1489:derived category 1473: 1471: 1470: 1465: 1454: 1451: 1442: 1440: 1439: 1434: 1422: 1420: 1419: 1414: 1403: 1400: 1391: 1389: 1388: 1383: 1367: 1365: 1364: 1359: 1343: 1341: 1340: 1335: 1324: 1321: 1312: 1310: 1309: 1304: 1289: 1287: 1286: 1281: 1270: 1267: 1258: 1256: 1255: 1250: 1248: 1247: 1231: 1229: 1228: 1223: 1211: 1209: 1208: 1203: 1187: 1185: 1184: 1179: 1153: 1152: 1125: 1122: 1111: 1110: 1088:Yoneda embedding 1085: 1083: 1082: 1077: 1066: 1063: 1055:is connected to 1054: 1052: 1051: 1046: 1034: 1032: 1031: 1026: 1024: 1023: 1004: 1002: 1001: 996: 985: 982: 970: 968: 967: 962: 947: 945: 944: 939: 928: 925: 916: 914: 913: 908: 896: 894: 893: 888: 876: 874: 873: 868: 856: 854: 853: 848: 837: 834: 825: 823: 822: 817: 779: 777: 776: 771: 766: 763: 742:derived category 707:Lawvere theories 670:category of sets 659: 657: 656: 651: 631: 630: 595: 593: 592: 587: 567: 566: 548: 513: 512: 431: 429: 428: 423: 421: 420: 404: 402: 401: 396: 394: 393: 381: 380: 354: 352: 351: 346: 344: 343: 317: 315: 314: 309: 307: 306: 287: 285: 284: 279: 274: 273: 261: 260: 239: 238: 223: 222: 201: 200: 172: 170: 169: 164: 144: 143: 125: 84: 83: 19:In mathematics, 2905: 2904: 2900: 2899: 2898: 2896: 2895: 2894: 2890:Category theory 2880: 2879: 2878: 2866: 2853: 2842:math.CT/0608040 2826: 2813: 2792: 2746: 2733: 2712: 2708: 2707: 2691: 2690: 2686: 2669:Neeman, Amnon. 2668: 2667: 2663: 2655: 2651: 2643: 2639: 2634: 2582:For categories 2580: 2545: 2544: 2519: 2518: 2515: 2491: 2490: 2471: 2470: 2438: 2427: 2426: 2405: 2387: 2382: 2381: 2360: 2346: 2345: 2305: 2300: 2299: 2273: 2268: 2267: 2236: 2215: 2214: 2193: 2192: 2173: 2172: 2150: 2149: 2126: 2125: 2102: 2094: 2093: 2090:quasi-separated 2062: 2061: 2020: 2015: 2014: 1991: 1990: 1984: 1960: 1959: 1936: 1929: 1924: 1923: 1894: 1887: 1870: 1849: 1833: 1832: 1810: 1809: 1739: 1734: 1733: 1704: 1697: 1684: 1662: 1643: 1642: 1620: 1619: 1592: 1582: 1564: 1563: 1541: 1540: 1493: 1492: 1485: 1480: 1445: 1444: 1425: 1424: 1394: 1393: 1374: 1373: 1350: 1349: 1315: 1314: 1295: 1294: 1261: 1260: 1239: 1234: 1233: 1214: 1213: 1194: 1193: 1144: 1096: 1091: 1090: 1057: 1056: 1037: 1036: 1012: 1007: 1006: 976: 975: 953: 952: 919: 918: 899: 898: 879: 878: 859: 858: 828: 827: 808: 807: 745: 744: 717:) of models of 666: 622: 617: 616: 558: 504: 499: 498: 477: 457: 447:call these the 412: 407: 406: 385: 372: 361: 360: 335: 324: 323: 298: 293: 292: 265: 252: 230: 214: 192: 181: 180: 135: 75: 70: 69: 65:if the functor 55:(also known as 41: 21:compact objects 17: 12: 11: 5: 2903: 2901: 2893: 2892: 2882: 2881: 2877: 2876: 2864: 2851: 2824: 2811: 2790: 2755:(4): 909–966, 2744: 2731: 2709: 2706: 2705: 2684: 2661: 2659:, Chapter 1.A) 2649: 2636: 2635: 2633: 2630: 2579: 2576: 2552: 2526: 2514: 2511: 2498: 2478: 2458: 2455: 2452: 2447: 2442: 2437: 2434: 2412: 2408: 2404: 2401: 2396: 2391: 2367: 2363: 2359: 2356: 2353: 2330: 2325: 2320: 2315: 2312: 2308: 2296: 2295: 2282: 2277: 2253: 2250: 2243: 2239: 2235: 2232: 2227: 2224: 2212: 2200: 2180: 2157: 2135: 2111: 2106: 2101: 2071: 2045: 2040: 2035: 2030: 2027: 2023: 2000: 1983: 1980: 1967: 1943: 1939: 1933: 1908: 1901: 1897: 1891: 1886: 1881: 1875: 1869: 1858: 1855: 1852: 1843: 1840: 1817: 1797: 1794: 1791: 1783: 1780: 1777: 1769: 1766: 1763: 1755: 1750: 1744: 1718: 1711: 1707: 1701: 1693: 1690: 1687: 1678: 1673: 1667: 1661: 1653: 1650: 1627: 1605: 1602: 1599: 1595: 1589: 1585: 1581: 1578: 1573: 1548: 1528: 1525: 1517: 1514: 1511: 1503: 1500: 1484: 1481: 1479: 1476: 1463: 1460: 1457: 1432: 1412: 1409: 1406: 1381: 1357: 1333: 1330: 1327: 1302: 1279: 1276: 1273: 1246: 1242: 1221: 1201: 1177: 1174: 1171: 1168: 1165: 1162: 1159: 1156: 1151: 1147: 1143: 1140: 1137: 1134: 1131: 1128: 1120: 1117: 1114: 1109: 1106: 1103: 1099: 1075: 1072: 1069: 1044: 1022: 1019: 1015: 994: 991: 988: 960: 937: 934: 931: 906: 886: 866: 846: 843: 840: 815: 769: 761: 758: 755: 752: 665: 662: 649: 646: 643: 640: 637: 634: 629: 625: 603:arises as the 597: 596: 585: 582: 579: 576: 573: 570: 565: 561: 557: 554: 551: 547: 544: 540: 537: 534: 531: 528: 525: 522: 519: 516: 511: 507: 476: 473: 456: 453: 419: 415: 392: 388: 384: 379: 375: 371: 368: 342: 338: 334: 331: 305: 301: 289: 288: 277: 272: 268: 264: 259: 255: 251: 248: 245: 242: 237: 233: 229: 226: 221: 217: 213: 210: 207: 204: 199: 195: 191: 188: 174: 173: 162: 159: 156: 153: 150: 147: 142: 138: 134: 131: 128: 124: 121: 118: 115: 111: 108: 105: 102: 99: 96: 93: 90: 87: 82: 78: 47:in a category 40: 37: 15: 13: 10: 9: 6: 4: 3: 2: 2902: 2891: 2888: 2887: 2885: 2874: 2870: 2865: 2862: 2858: 2854: 2848: 2843: 2838: 2834: 2830: 2825: 2822: 2818: 2814: 2808: 2804: 2800: 2796: 2791: 2788: 2784: 2780: 2776: 2772: 2768: 2763: 2758: 2754: 2750: 2745: 2742: 2738: 2734: 2732:0-521-42261-2 2728: 2724: 2720: 2716: 2711: 2710: 2700: 2695: 2688: 2685: 2680: 2676: 2672: 2665: 2662: 2658: 2653: 2650: 2646: 2641: 2638: 2631: 2629: 2627: 2623: 2619: 2615: 2611: 2607: 2603: 2599: 2598: 2593: 2589: 2585: 2577: 2575: 2573: 2568: 2566: 2550: 2542: 2541: 2524: 2512: 2510: 2496: 2476: 2453: 2445: 2435: 2432: 2410: 2406: 2402: 2394: 2365: 2361: 2357: 2354: 2351: 2342: 2313: 2310: 2306: 2280: 2248: 2241: 2237: 2233: 2230: 2222: 2213: 2198: 2178: 2171: 2170: 2169: 2155: 2109: 2099: 2091: 2087: 2086:quasi-compact 2059: 2028: 2025: 2021: 1989: 1981: 1979: 1965: 1941: 1937: 1919: 1899: 1895: 1884: 1879: 1856: 1853: 1850: 1841: 1838: 1829: 1815: 1781: 1778: 1764: 1753: 1748: 1729: 1709: 1705: 1691: 1688: 1685: 1676: 1671: 1651: 1648: 1639: 1625: 1603: 1600: 1597: 1587: 1583: 1576: 1562: 1546: 1515: 1512: 1498: 1490: 1482: 1477: 1475: 1458: 1430: 1407: 1379: 1371: 1355: 1347: 1328: 1300: 1291: 1274: 1244: 1240: 1219: 1199: 1191: 1172: 1169: 1166: 1160: 1157: 1154: 1149: 1145: 1138: 1135: 1129: 1115: 1112: 1104: 1097: 1089: 1070: 1042: 1020: 1017: 1013: 989: 974: 958: 949: 932: 904: 884: 864: 841: 813: 805: 801: 797: 793: 789: 787: 783: 759: 756: 750: 743: 738: 736: 732: 728: 724: 720: 716: 712: 708: 704: 699: 697: 693: 690: 686: 684: 678: 673: 671: 663: 661: 644: 641: 638: 632: 627: 623: 614: 610: 606: 602: 580: 577: 574: 568: 563: 559: 552: 549: 535: 532: 526: 523: 520: 514: 509: 505: 497: 496: 495: 493: 492:Neeman (2001) 489: 485: 482: 474: 472: 470: 466: 462: 454: 452: 450: 446: 442: 438: 433: 417: 413: 390: 386: 382: 377: 373: 366: 358: 340: 336: 329: 321: 303: 299: 270: 266: 262: 257: 253: 249: 246: 240: 235: 231: 219: 215: 211: 208: 202: 197: 193: 189: 186: 179: 178: 177: 157: 154: 151: 145: 140: 136: 129: 126: 106: 103: 97: 94: 91: 85: 80: 76: 68: 67: 66: 64: 63: 58: 57:direct limits 54: 50: 46: 38: 36: 34: 30: 26: 22: 2868: 2828: 2794: 2752: 2748: 2714: 2687: 2678: 2674: 2664: 2652: 2640: 2621: 2613: 2609: 2605: 2601: 2595: 2587: 2583: 2581: 2569: 2564: 2539: 2538: 2516: 2343: 2297: 1985: 1921: 1831: 1731: 1641: 1486: 1478:Non-examples 1369: 1292: 1189: 950: 795: 790: 781: 739: 734: 730: 726: 722: 718: 714: 710: 700: 695: 691: 682: 681:category of 676: 674: 667: 612: 600: 598: 483: 478: 468: 460: 458: 448: 440: 434: 356: 319: 290: 175: 61: 60: 59:) is called 48: 44: 42: 28: 24: 20: 18: 2645:Lurie (2009 1346:ind-objects 675:For a ring 355:, for some 2681:: 483–488. 2632:References 2597:dualizable 2168:such that 1561:open cover 1372:object of 973:presheaves 488:coproducts 465:∞-category 43:An object 39:Definition 2762:0805.0157 2699:1405.1888 2647:, §5.3.4) 2436:∈ 2400:→ 2252:¯ 2238:⊗ 2226:¯ 1880:∙ 1864: Hom 1854:∈ 1842:∈ 1839:ψ 1816:ϕ 1754:∈ 1749:∙ 1732:for some 1689:∈ 1672:∙ 1652:∈ 1649:ϕ 1601:∈ 1167:− 1161:⁡ 1142:↦ 1119:→ 1105:− 760:− 703:varieties 645:− 633:⁡ 569:⁡ 556:↦ 539:→ 527:⋅ 515:⁡ 383:⁡ 370:→ 333:→ 263:⁡ 241:⁡ 228:→ 203:⁡ 190:⁡ 146:⁡ 133:↦ 110:→ 98:⋅ 86:⁡ 2884:Category 685:-modules 664:Examples 33:category 2861:2522659 2821:2182076 2787:2202294 2779:2669705 2741:1294136 2489:at the 1192:object 1086:by the 62:compact 2859:  2849:  2819:  2809:  2785:  2777:  2739:  2729:  1268:PreShv 1188:. For 1123:PreShv 1064:PreShv 983:PreShv 479:For a 463:is an 2837:arXiv 2783:S2CID 2757:arXiv 2694:arXiv 1847:colim 1682:colim 607:of a 374:colim 254:colim 187:colim 27:, or 2847:ISBN 2807:ISBN 2727:ISBN 2088:and 1986:For 926:Open 835:Open 794:are 2799:doi 2767:doi 2719:doi 2537:is 2084:is 2056:of 1656:Hom 1474:). 1452:Ind 1401:Ind 1370:any 1348:in 1344:of 1322:Ind 1290:). 1212:of 1190:any 1158:Hom 951:If 796:not 780:of 764:Mod 624:Hom 560:Hom 506:Hom 318:in 232:Hom 194:Hom 137:Hom 77:Hom 2886:: 2857:MR 2855:, 2845:, 2835:, 2817:MR 2815:, 2805:, 2781:, 2775:MR 2773:, 2765:, 2753:23 2751:, 2737:MR 2735:, 2725:, 2677:. 2673:. 2628:. 2574:. 1786:Ab 1772:Sh 1758:Ob 1520:Ab 1506:Sh 1232:, 1155::= 948:. 788:. 490:, 451:. 432:. 2839:: 2801:: 2769:: 2759:: 2721:: 2702:. 2696:: 2679:6 2622:R 2614:R 2610:R 2606:R 2602:C 2588:C 2584:C 2565:V 2551:C 2525:C 2497:n 2477:x 2457:) 2454:S 2451:( 2446:a 2441:G 2433:x 2411:n 2407:L 2403:G 2395:a 2390:G 2366:n 2362:L 2358:G 2355:= 2352:G 2329:) 2324:X 2319:( 2314:c 2311:q 2307:D 2281:a 2276:G 2249:k 2242:k 2234:G 2231:= 2223:G 2199:k 2179:G 2156:G 2134:X 2110:a 2105:G 2100:B 2070:X 2044:) 2039:X 2034:( 2029:c 2026:q 2022:D 1999:X 1966:X 1942:i 1938:U 1932:Z 1907:) 1900:i 1896:U 1890:Z 1885:, 1874:F 1868:( 1857:I 1851:i 1796:) 1793:) 1790:) 1782:; 1779:X 1776:( 1768:( 1765:D 1762:( 1743:F 1717:) 1710:i 1706:U 1700:Z 1692:I 1686:i 1677:, 1666:F 1660:( 1626:X 1604:I 1598:i 1594:} 1588:i 1584:U 1580:{ 1577:= 1572:U 1547:X 1527:) 1524:) 1516:; 1513:X 1510:( 1502:( 1499:D 1462:) 1459:C 1456:( 1431:C 1411:) 1408:C 1405:( 1380:C 1356:C 1332:) 1329:C 1326:( 1301:C 1278:) 1275:C 1272:( 1245:X 1241:h 1220:C 1200:X 1176:) 1173:X 1170:, 1164:( 1150:X 1146:h 1139:X 1136:, 1133:) 1130:C 1127:( 1116:C 1113:: 1108:) 1102:( 1098:h 1074:) 1071:C 1068:( 1043:C 1021:p 1018:o 1014:C 993:) 990:C 987:( 959:C 936:) 933:X 930:( 905:X 885:X 865:X 845:) 842:X 839:( 814:X 782:R 768:) 757:R 754:( 751:D 735:T 731:T 727:T 723:T 719:T 715:T 711:T 696:R 692:R 683:R 677:R 648:) 642:, 639:X 636:( 628:C 613:C 601:C 584:) 581:Y 578:, 575:X 572:( 564:C 553:Y 550:, 546:b 543:A 536:C 533:: 530:) 524:, 521:X 518:( 510:C 484:C 469:C 461:C 418:i 414:Y 391:i 387:Y 378:i 367:X 357:i 341:i 337:Y 330:X 320:C 304:i 300:Y 276:) 271:i 267:Y 258:i 250:, 247:X 244:( 236:C 225:) 220:i 216:Y 212:, 209:X 206:( 198:C 161:) 158:Y 155:, 152:X 149:( 141:C 130:Y 127:, 123:s 120:t 117:e 114:S 107:C 104:: 101:) 95:, 92:X 89:( 81:C 49:C 45:X

Index

category
filtered colimits
direct limits
Adámek & Rosický (1994)
Kashiwara & Schapira (2006)
∞-category
triangulated category
coproducts
Neeman (2001)
homotopy category
stable ∞-category
category of sets
category of R-modules
finitely presented
varieties
Lawvere theories
derived category
perfect complexes
Compact topological spaces
category of topological spaces
discrete topology
presheaves
Yoneda embedding
ind-objects
derived category
open cover
algebraic stacks
quasi-coherent sheaves
quasi-compact
quasi-separated

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