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Completion of a ring

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have similar looking singularities at the origin when viewing their graphs (both look like a plus sign). Notice that in the second case, any Zariski neighborhood of the origin is still an irreducible curve. If we use completions, then we are looking at a "small enough" neighborhood where the node has
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Since both rings are given by the intersection of two ideals generated by a homogeneous degree 1 polynomial, we can see algebraically that the singularities "look" the same. This is because such a scheme is the union of two non-equal linear subspaces of the affine plane.
2288: 1584: 752: 219: 2779: 469:{\displaystyle {\widehat {E}}=\varprojlim (E/F^{n}E)=\left\{\left.({\overline {a_{n}}})_{n\geq 0}\in \prod _{n\geq 0}(E/F^{n}E)\;\right|\;a_{i}\equiv a_{j}{\pmod {F^{i}E}}{\text{ for all }}i\leq j\right\}.\,} 2477: 2381: 2655: 1069: 862: 1273: 1669: 969: 1823: 1311: 2523: 2000: 1413: 2116: 1916: 1116: 1734: 631: 1160: 2822: 2555: 2108: 2914: 1182: 2062: 507:, then its completion is again an object with the same structure that is complete in the topology determined by the filtration. This construction may be applied both to 543: 1856: 2703: 2020: 1453: 1433: 1352: 1464: 663: 2324: 149: 2710: 2420: 2600: 992: 791: 3064: 1216: 17: 1593: 920: 3097: 3089: 1742: 1278: 2484: 1921: 2306:
The completion of a Noetherian local ring with respect to the unique maximal ideal is a Noetherian local ring.
1357: 3081: 28: 2283:{\displaystyle u=x{\sqrt {1+x}}=\sum _{n=0}^{\infty }{\frac {(-1)^{n}(2n)!}{(1-2n)(n!)^{2}(4^{n})}}x^{n+1}.} 3157: 3152: 638: 1861: 1085: 2661:
Together with the previous property, this implies that the functor of completion on finitely generated
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centered at the point are convergent. An algebraic completion is constructed in a manner analogous to
2803: 2528: 2067: 1473: 2673:. In particular, taking quotients of rings commutes with completion, meaning that for any quotient 141: 121: 2844: 1165: 3114: 2788: 2025: 63: 879:
is injective if and only if this intersection reduces to the zero element of the ring; by the
546: 2948: 102: 518: 3103: 2670: 1829: 1679: 903: 500: 51: 8: 2680: 1318: 575: 564: 512: 3119: 2963: 2005: 1675: 1438: 1418: 1337: 1079: 75: 59: 47: 1579:{\displaystyle {\begin{cases}R]\to {\widehat {R}}_{I}\\x_{i}\mapsto f_{i}\end{cases}}} 224:
of subgroups. One then defines the completion (with respect to the filtration) as the
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The completion of a Noetherian ring with respect to some ideal is a Noetherian ring.
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is an image of a formal power series ring, specifically, the image of the surjection
3133: 3128: 3052: 568: 508: 496: 67: 55: 35: 3100: 2958: 2562: 1202: 1128: 888: 884: 747:{\displaystyle F^{0}R=R\supset I\supset I^{2}\supset \cdots ,\quad F^{n}R=I^{n}.} 110: 491:
has additional algebraic structure compatible with the filtration, for instance
3073: 3048: 634: 582: 3146: 2938: 2825: 2666: 778: 598: 590: 558: 225: 137: 98: 70:. Complete commutative rings have a simpler structure than general ones, and 2983: 2953: 504: 106: 633:
is especially important, for example the distinguished maximal ideal of a
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two components. Taking the localizations of these rings along the ideal
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be the maximal ideal generated by the variables. Then the completion
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from the ring to its completion is the intersection of the powers of
214:{\displaystyle E=F^{0}E\supset F^{1}E\supset F^{2}E\supset \cdots \,} 2774:{\displaystyle {\widehat {R/I}}\cong {\widehat {R}}/{\widehat {I}}.} 3115:"On Hausdorff completions of commutative rings in rigid geometry" 43: 2472:{\displaystyle {\widehat {f}}:{\widehat {M}}\to {\widehat {N}},} 2376:{\displaystyle {\widehat {f}}:{\widehat {R}}\to {\widehat {S}}.} 66:, and together they are among the most basic tools in analysing 2321:
of topological rings gives rise to a map of their completions,
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Completions can also be used to analyze the local structure of
2650:{\displaystyle {\widehat {M}}=M\otimes _{R}{\widehat {R}}.} 2309:
The completion is a functorial operation: a continuous map
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Commutative algebra. With a view toward algebraic geometry
1064:{\displaystyle {\widehat {M}}_{I}=\varprojlim (M/I^{n}M).} 910:-adic topology. A basis of open neighborhoods of a module 3084:, 150. Springer-Verlag, New York, 1995. xvi+785 pp.  857:{\displaystyle {\widehat {R}}_{I}=\varprojlim (R/I^{n})} 867:
pronounced "R I hat". The kernel of the canonical map
94:: heuristically, this is a neighborhood so small that 2847: 2806: 2713: 2683: 2603: 2531: 2487: 2423: 2327: 2119: 2070: 2028: 2008: 1924: 1864: 1832: 1745: 1688: 1596: 1467: 1441: 1421: 1360: 1340: 1281: 1268:{\displaystyle {\mathfrak {m}}=(x_{1},\ldots ,x_{n})} 1219: 1168: 1139: 1088: 995: 923: 794: 666: 609: 521: 237: 152: 515:. As may be expected, when the intersection of the 3108: 2908: 2816: 2773: 2697: 2649: 2549: 2517: 2471: 2375: 2282: 2102: 2056: 2014: 1994: 1910: 1850: 1817: 1728: 1664:{\displaystyle (x_{1}-f_{1},\ldots ,x_{n}-f_{n}).} 1663: 1578: 1447: 1427: 1407: 1346: 1305: 1267: 1176: 1154: 1110: 1063: 964:{\displaystyle x+I^{n}M\quad {\text{for }}x\in M.} 963: 856: 746: 625: 537: 468: 213: 3144: 1682:. For example, the affine schemes associated to 3047: 3030: 3018: 3006: 2800:Noetherian commutative ring with maximal ideal 2415:uniquely extends to the map of the completions: 2395:are two modules over the same topological ring 1818:{\displaystyle \mathbb {C} /(y^{2}-x^{2}(1+x))} 2579:The completion of a finitely generated module 1306:{\displaystyle {\widehat {R}}_{\mathfrak {m}}} 2518:{\displaystyle {\widehat {M}},{\widehat {N}}} 1995:{\displaystyle \mathbb {C} ]/((y+u)(y-u))} 393: 387: 3132: 2072: 1926: 1866: 1747: 1690: 1170: 1142: 465: 210: 1408:{\displaystyle I=(f_{1},\ldots ,f_{n}),} 1074:This procedure converts any module over 479:This is again an abelian group. Usually 3021:, Proposition 10.16. and Theorem 10.26. 883:, this is the case for any commutative 127: 14: 3145: 986:is the inverse limit of the quotients 113:, and agrees with it in the case when 78:, a completion of a ring of functions 653:and form a descending filtration on 3057:Introduction to Commutative Algebra 2809: 2110:More explicitly, the power series: 1297: 1222: 1162:is obtained by completing the ring 618: 425: 24: 2161: 1911:{\displaystyle \mathbb {C} ]/(xy)} 1111:{\displaystyle {\widehat {R}}_{I}} 25: 3169: 1729:{\displaystyle \mathbb {C} /(xy)} 914:is given by the sets of the form 626:{\displaystyle I={\mathfrak {m}}} 552: 2411:is a continuous module map then 1155:{\displaystyle \mathbb {Z} _{p}} 2817:{\displaystyle {\mathfrak {m}}} 2792:(equicharacteristic case). Let 2550:{\displaystyle {\widehat {R}}.} 943: 898:There is a related topology on 714: 418: 3134:10.1016/j.jalgebra.2011.02.001 3024: 3012: 3000: 2976: 2895: 2892: 2860: 2857: 2451: 2355: 2255: 2242: 2233: 2223: 2220: 2205: 2197: 2188: 2179: 2169: 2103:{\displaystyle \mathbb {C} ].} 2094: 2091: 2079: 2076: 2051: 2039: 1989: 1986: 1974: 1971: 1959: 1956: 1948: 1945: 1933: 1930: 1905: 1896: 1888: 1885: 1873: 1870: 1845: 1833: 1812: 1809: 1797: 1771: 1763: 1751: 1723: 1714: 1706: 1694: 1655: 1597: 1556: 1520: 1517: 1514: 1482: 1479: 1399: 1367: 1262: 1230: 1055: 1031: 851: 830: 439: 419: 384: 360: 326: 305: 290: 266: 13: 1: 3082:Graduate Texts in Mathematics 3040: 2297: 2022:is the formal square root of 545:equals zero, this produces a 2969: 2909:{\displaystyle R\simeq K]/I} 1177:{\displaystyle \mathbb {Z} } 639:basis of open neighbourhoods 581:determines the Krull (after 320: 62:. Completion is similar to 7: 3031:Atiyah & Macdonald 1969 3019:Atiyah & Macdonald 1969 3007:Atiyah & Macdonald 1969 2984:"Stacks Project — Tag 0316" 2932: 1121: 757:(Open neighborhoods of any 10: 3174: 2705:, there is an isomorphism 2057:{\displaystyle x^{2}(1+x)} 1184:of integers at the ideal ( 881:Krull intersection theorem 574:by the powers of a proper 556: 42:is any of several related 26: 3113:; Kato, Fumiharu (2011). 777:-adic) completion is the 547:complete topological ring 2988:stacks.math.columbia.edu 2928:(Eisenbud, Theorem 7.7). 1590:The kernel is the ideal 1334:Given a noetherian ring 117:has a metric given by a 54:that result in complete 3049:Atiyah, Michael Francis 2789:Cohen structure theorem 2583:over a Noetherian ring 1209:variables over a field 978:-adic completion of an 906:, also called Krull or 645:is given by the powers 2910: 2835:contains a field, then 2818: 2775: 2699: 2651: 2551: 2519: 2473: 2377: 2284: 2165: 2104: 2058: 2016: 1996: 1912: 1852: 1819: 1730: 1665: 1580: 1449: 1429: 1409: 1348: 1307: 1269: 1178: 1156: 1112: 1065: 965: 858: 748: 627: 567:, the filtration on a 539: 538:{\displaystyle F^{i}E} 470: 215: 2949:Locally compact field 2911: 2819: 2776: 2700: 2671:short exact sequences 2652: 2552: 2520: 2474: 2378: 2285: 2145: 2105: 2059: 2017: 1997: 1913: 1858:and completing gives 1853: 1851:{\displaystyle (x,y)} 1820: 1731: 1666: 1581: 1450: 1430: 1410: 1349: 1308: 1270: 1179: 1157: 1113: 1066: 966: 859: 749: 628: 540: 471: 216: 3109:Fujiwara, Kazuhiro; 3033:, Proposition 10.14. 2845: 2804: 2711: 2681: 2601: 2589:extension of scalars 2561:The completion of a 2529: 2485: 2421: 2325: 2117: 2068: 2026: 2006: 2002:respectively, where 1922: 1862: 1830: 1743: 1736:and the nodal cubic 1686: 1594: 1465: 1439: 1435:-adic completion of 1419: 1358: 1338: 1279: 1217: 1166: 1137: 1086: 993: 921: 792: 765:are given by cosets 664: 607: 519: 513:noncommutative rings 235: 150: 128:General construction 74:applies to them. In 27:For other uses, see 18:Completion (algebra) 3158:Topological algebra 3153:Commutative algebra 2698:{\displaystyle R/I} 2587:can be obtained by 1319:formal power series 565:commutative algebra 445: for all  88:formal neighborhood 3120:Journal of Algebra 3059:. Westview Press. 2964:Quasi-unmixed ring 2906: 2814: 2771: 2695: 2647: 2547: 2515: 2469: 2373: 2280: 2100: 2054: 2012: 1992: 1908: 1848: 1815: 1726: 1661: 1576: 1571: 1445: 1425: 1405: 1344: 1303: 1265: 1174: 1152: 1108: 1080:topological module 1061: 1026: 961: 854: 825: 744: 623: 535: 487:abelian group. If 466: 359: 261: 211: 140:with a descending 86:concentrates on a 76:algebraic geometry 3066:978-0-201-40751-8 2944:Profinite integer 2765: 2748: 2733: 2641: 2613: 2541: 2525:are modules over 2512: 2497: 2463: 2448: 2433: 2367: 2352: 2337: 2259: 2140: 2015:{\displaystyle u} 1533: 1448:{\displaystyle R} 1428:{\displaystyle I} 1347:{\displaystyle R} 1292: 1099: 1019: 1006: 947: 818: 805: 446: 344: 323: 254: 247: 68:commutative rings 56:topological rings 16:(Redirected from 3165: 3138: 3136: 3070: 3034: 3028: 3022: 3016: 3010: 3009:, Theorem 10.26. 3004: 2998: 2997: 2995: 2994: 2980: 2915: 2913: 2912: 2907: 2902: 2891: 2890: 2872: 2871: 2823: 2821: 2820: 2815: 2813: 2812: 2780: 2778: 2777: 2772: 2767: 2766: 2758: 2755: 2750: 2749: 2741: 2735: 2734: 2729: 2725: 2716: 2704: 2702: 2701: 2696: 2691: 2656: 2654: 2653: 2648: 2643: 2642: 2634: 2631: 2630: 2615: 2614: 2606: 2556: 2554: 2553: 2548: 2543: 2542: 2534: 2524: 2522: 2521: 2516: 2514: 2513: 2505: 2499: 2498: 2490: 2478: 2476: 2475: 2470: 2465: 2464: 2456: 2450: 2449: 2441: 2435: 2434: 2426: 2382: 2380: 2379: 2374: 2369: 2368: 2360: 2354: 2353: 2345: 2339: 2338: 2330: 2289: 2287: 2286: 2281: 2276: 2275: 2260: 2258: 2254: 2253: 2241: 2240: 2203: 2187: 2186: 2167: 2164: 2159: 2141: 2130: 2109: 2107: 2106: 2101: 2075: 2063: 2061: 2060: 2055: 2038: 2037: 2021: 2019: 2018: 2013: 2001: 1999: 1998: 1993: 1955: 1929: 1917: 1915: 1914: 1909: 1895: 1869: 1857: 1855: 1854: 1849: 1824: 1822: 1821: 1816: 1796: 1795: 1783: 1782: 1770: 1750: 1735: 1733: 1732: 1727: 1713: 1693: 1670: 1668: 1667: 1662: 1654: 1653: 1641: 1640: 1622: 1621: 1609: 1608: 1585: 1583: 1582: 1577: 1575: 1574: 1568: 1567: 1555: 1554: 1541: 1540: 1535: 1534: 1526: 1513: 1512: 1494: 1493: 1454: 1452: 1451: 1446: 1434: 1432: 1431: 1426: 1414: 1412: 1411: 1406: 1398: 1397: 1379: 1378: 1353: 1351: 1350: 1345: 1312: 1310: 1309: 1304: 1302: 1301: 1300: 1294: 1293: 1285: 1274: 1272: 1271: 1266: 1261: 1260: 1242: 1241: 1226: 1225: 1183: 1181: 1180: 1175: 1173: 1161: 1159: 1158: 1153: 1151: 1150: 1145: 1117: 1115: 1114: 1109: 1107: 1106: 1101: 1100: 1092: 1078:into a complete 1070: 1068: 1067: 1062: 1051: 1050: 1041: 1027: 1014: 1013: 1008: 1007: 999: 970: 968: 967: 962: 948: 945: 939: 938: 878: 870: 863: 861: 860: 855: 850: 849: 840: 826: 813: 812: 807: 806: 798: 753: 751: 750: 745: 740: 739: 724: 723: 704: 703: 676: 675: 632: 630: 629: 624: 622: 621: 597:. The case of a 569:commutative ring 544: 542: 541: 536: 531: 530: 503:, or a filtered 475: 473: 472: 467: 461: 457: 447: 444: 442: 435: 434: 416: 415: 403: 402: 392: 388: 380: 379: 370: 358: 340: 339: 324: 319: 318: 309: 286: 285: 276: 262: 249: 248: 240: 220: 218: 217: 212: 200: 199: 184: 183: 168: 167: 111:Cauchy sequences 36:abstract algebra 21: 3173: 3172: 3168: 3167: 3166: 3164: 3163: 3162: 3143: 3142: 3141: 3067: 3053:Macdonald, I.G. 3043: 3038: 3037: 3029: 3025: 3017: 3013: 3005: 3001: 2992: 2990: 2982: 2981: 2977: 2972: 2959:Linear topology 2935: 2924:and some ideal 2898: 2886: 2882: 2867: 2863: 2846: 2843: 2842: 2808: 2807: 2805: 2802: 2801: 2757: 2756: 2751: 2740: 2739: 2721: 2717: 2715: 2714: 2712: 2709: 2708: 2687: 2682: 2679: 2678: 2669:: it preserves 2633: 2632: 2626: 2622: 2605: 2604: 2602: 2599: 2598: 2563:Noetherian ring 2533: 2532: 2530: 2527: 2526: 2504: 2503: 2489: 2488: 2486: 2483: 2482: 2455: 2454: 2440: 2439: 2425: 2424: 2422: 2419: 2418: 2359: 2358: 2344: 2343: 2329: 2328: 2326: 2323: 2322: 2300: 2265: 2261: 2249: 2245: 2236: 2232: 2204: 2182: 2178: 2168: 2166: 2160: 2149: 2129: 2118: 2115: 2114: 2071: 2069: 2066: 2065: 2033: 2029: 2027: 2024: 2023: 2007: 2004: 2003: 1951: 1925: 1923: 1920: 1919: 1891: 1865: 1863: 1860: 1859: 1831: 1828: 1827: 1791: 1787: 1778: 1774: 1766: 1746: 1744: 1741: 1740: 1709: 1689: 1687: 1684: 1683: 1649: 1645: 1636: 1632: 1617: 1613: 1604: 1600: 1595: 1592: 1591: 1570: 1569: 1563: 1559: 1550: 1546: 1543: 1542: 1536: 1525: 1524: 1523: 1508: 1504: 1489: 1485: 1469: 1468: 1466: 1463: 1462: 1440: 1437: 1436: 1420: 1417: 1416: 1393: 1389: 1374: 1370: 1359: 1356: 1355: 1339: 1336: 1335: 1325:variables over 1296: 1295: 1284: 1283: 1282: 1280: 1277: 1276: 1256: 1252: 1237: 1233: 1221: 1220: 1218: 1215: 1214: 1203:polynomial ring 1169: 1167: 1164: 1163: 1146: 1141: 1140: 1138: 1135: 1134: 1124: 1102: 1091: 1090: 1089: 1087: 1084: 1083: 1046: 1042: 1037: 1018: 1009: 998: 997: 996: 994: 991: 990: 944: 934: 930: 922: 919: 918: 889:integral domain 885:Noetherian ring 876: 868: 845: 841: 836: 817: 808: 797: 796: 795: 793: 790: 789: 735: 731: 719: 715: 699: 695: 671: 667: 665: 662: 661: 617: 616: 608: 605: 604: 561: 555: 526: 522: 520: 517: 516: 443: 430: 426: 417: 411: 407: 398: 394: 375: 371: 366: 348: 329: 325: 314: 310: 308: 304: 301: 300: 296: 281: 277: 272: 253: 239: 238: 236: 233: 232: 195: 191: 179: 175: 163: 159: 151: 148: 147: 130: 119:non-Archimedean 32: 23: 22: 15: 12: 11: 5: 3171: 3161: 3160: 3155: 3140: 3139: 3127:(1): 293–321. 3106: 3074:David Eisenbud 3071: 3065: 3044: 3042: 3039: 3036: 3035: 3023: 3011: 2999: 2974: 2973: 2971: 2968: 2967: 2966: 2961: 2956: 2951: 2946: 2941: 2934: 2931: 2930: 2929: 2918: 2917: 2916: 2905: 2901: 2897: 2894: 2889: 2885: 2881: 2878: 2875: 2870: 2866: 2862: 2859: 2856: 2853: 2850: 2837: 2836: 2811: 2796:be a complete 2784: 2783: 2782: 2781: 2770: 2764: 2761: 2754: 2747: 2744: 2738: 2732: 2728: 2724: 2720: 2694: 2690: 2686: 2659: 2658: 2657: 2646: 2640: 2637: 2629: 2625: 2621: 2618: 2612: 2609: 2593: 2592: 2577: 2558: 2557: 2546: 2540: 2537: 2511: 2508: 2502: 2496: 2493: 2479: 2468: 2462: 2459: 2453: 2447: 2444: 2438: 2432: 2429: 2416: 2384: 2383: 2372: 2366: 2363: 2357: 2351: 2348: 2342: 2336: 2333: 2307: 2304: 2299: 2296: 2291: 2290: 2279: 2274: 2271: 2268: 2264: 2257: 2252: 2248: 2244: 2239: 2235: 2231: 2228: 2225: 2222: 2219: 2216: 2213: 2210: 2207: 2202: 2199: 2196: 2193: 2190: 2185: 2181: 2177: 2174: 2171: 2163: 2158: 2155: 2152: 2148: 2144: 2139: 2136: 2133: 2128: 2125: 2122: 2099: 2096: 2093: 2090: 2087: 2084: 2081: 2078: 2074: 2053: 2050: 2047: 2044: 2041: 2036: 2032: 2011: 1991: 1988: 1985: 1982: 1979: 1976: 1973: 1970: 1967: 1964: 1961: 1958: 1954: 1950: 1947: 1944: 1941: 1938: 1935: 1932: 1928: 1907: 1904: 1901: 1898: 1894: 1890: 1887: 1884: 1881: 1878: 1875: 1872: 1868: 1847: 1844: 1841: 1838: 1835: 1814: 1811: 1808: 1805: 1802: 1799: 1794: 1790: 1786: 1781: 1777: 1773: 1769: 1765: 1762: 1759: 1756: 1753: 1749: 1725: 1722: 1719: 1716: 1712: 1708: 1705: 1702: 1699: 1696: 1692: 1672: 1671: 1660: 1657: 1652: 1648: 1644: 1639: 1635: 1631: 1628: 1625: 1620: 1616: 1612: 1607: 1603: 1599: 1588: 1587: 1586: 1573: 1566: 1562: 1558: 1553: 1549: 1545: 1544: 1539: 1532: 1529: 1522: 1519: 1516: 1511: 1507: 1503: 1500: 1497: 1492: 1488: 1484: 1481: 1478: 1475: 1474: 1472: 1457: 1456: 1444: 1424: 1404: 1401: 1396: 1392: 1388: 1385: 1382: 1377: 1373: 1369: 1366: 1363: 1343: 1331: 1330: 1299: 1291: 1288: 1264: 1259: 1255: 1251: 1248: 1245: 1240: 1236: 1232: 1229: 1224: 1190: 1189: 1172: 1149: 1144: 1132:-adic integers 1123: 1120: 1105: 1098: 1095: 1072: 1071: 1060: 1057: 1054: 1049: 1045: 1040: 1036: 1033: 1030: 1025: 1022: 1017: 1012: 1005: 1002: 972: 971: 960: 957: 954: 951: 942: 937: 933: 929: 926: 865: 864: 853: 848: 844: 839: 835: 832: 829: 824: 821: 816: 811: 804: 801: 755: 754: 743: 738: 734: 730: 727: 722: 718: 713: 710: 707: 702: 698: 694: 691: 688: 685: 682: 679: 674: 670: 635:valuation ring 620: 615: 612: 583:Wolfgang Krull 557:Main article: 554: 553:Krull topology 551: 534: 529: 525: 477: 476: 464: 460: 456: 453: 450: 441: 438: 433: 429: 424: 421: 414: 410: 406: 401: 397: 391: 386: 383: 378: 374: 369: 365: 362: 357: 354: 351: 347: 343: 338: 335: 332: 328: 322: 317: 313: 307: 303: 299: 295: 292: 289: 284: 280: 275: 271: 268: 265: 260: 257: 252: 246: 243: 222: 221: 209: 206: 203: 198: 194: 190: 187: 182: 178: 174: 171: 166: 162: 158: 155: 129: 126: 122:absolute value 90:of a point of 72:Hensel's lemma 9: 6: 4: 3: 2: 3170: 3159: 3156: 3154: 3151: 3150: 3148: 3135: 3130: 3126: 3122: 3121: 3116: 3112: 3107: 3105: 3102: 3099: 3098:0-387-94269-6 3095: 3091: 3090:0-387-94268-8 3087: 3083: 3079: 3075: 3072: 3068: 3062: 3058: 3054: 3050: 3046: 3045: 3032: 3027: 3020: 3015: 3008: 3003: 2989: 2985: 2979: 2975: 2965: 2962: 2960: 2957: 2955: 2952: 2950: 2947: 2945: 2942: 2940: 2939:Formal scheme 2937: 2936: 2927: 2923: 2919: 2903: 2899: 2887: 2883: 2879: 2876: 2873: 2868: 2864: 2854: 2851: 2848: 2841: 2840: 2839: 2838: 2834: 2830: 2827: 2826:residue field 2799: 2795: 2791: 2790: 2786: 2785: 2768: 2762: 2759: 2752: 2745: 2742: 2736: 2730: 2726: 2722: 2718: 2707: 2706: 2692: 2688: 2684: 2676: 2672: 2668: 2664: 2660: 2644: 2638: 2635: 2627: 2623: 2619: 2616: 2610: 2607: 2597: 2596: 2595: 2594: 2590: 2586: 2582: 2578: 2575: 2571: 2567: 2564: 2560: 2559: 2544: 2538: 2535: 2509: 2506: 2500: 2494: 2491: 2480: 2466: 2460: 2457: 2445: 2442: 2436: 2430: 2427: 2417: 2414: 2410: 2407: →  2406: 2402: 2398: 2394: 2390: 2387:Moreover, if 2386: 2385: 2370: 2364: 2361: 2349: 2346: 2340: 2334: 2331: 2320: 2317: →  2316: 2312: 2308: 2305: 2302: 2301: 2295: 2277: 2272: 2269: 2266: 2262: 2250: 2246: 2237: 2229: 2226: 2217: 2214: 2211: 2208: 2200: 2194: 2191: 2183: 2175: 2172: 2156: 2153: 2150: 2146: 2142: 2137: 2134: 2131: 2126: 2123: 2120: 2113: 2112: 2111: 2097: 2088: 2085: 2082: 2048: 2045: 2042: 2034: 2030: 2009: 1983: 1980: 1977: 1968: 1965: 1962: 1952: 1942: 1939: 1936: 1902: 1899: 1892: 1882: 1879: 1876: 1842: 1839: 1836: 1806: 1803: 1800: 1792: 1788: 1784: 1779: 1775: 1767: 1760: 1757: 1754: 1739: 1720: 1717: 1710: 1703: 1700: 1697: 1681: 1677: 1676:singularities 1658: 1650: 1646: 1642: 1637: 1633: 1629: 1626: 1623: 1618: 1614: 1610: 1605: 1601: 1589: 1564: 1560: 1551: 1547: 1537: 1530: 1527: 1509: 1505: 1501: 1498: 1495: 1490: 1486: 1476: 1470: 1461: 1460: 1459: 1458: 1442: 1422: 1402: 1394: 1390: 1386: 1383: 1380: 1375: 1371: 1364: 1361: 1354:and an ideal 1341: 1333: 1332: 1328: 1324: 1320: 1316: 1289: 1286: 1257: 1253: 1249: 1246: 1243: 1238: 1234: 1227: 1212: 1208: 1204: 1200: 1196: 1192: 1191: 1187: 1147: 1133: 1131: 1126: 1125: 1119: 1103: 1096: 1093: 1081: 1077: 1058: 1052: 1047: 1043: 1038: 1034: 1028: 1023: 1020: 1015: 1010: 1003: 1000: 989: 988: 987: 985: 981: 977: 958: 955: 952: 949: 940: 935: 931: 927: 924: 917: 916: 915: 913: 909: 905: 901: 896: 894: 890: 886: 882: 874: 846: 842: 837: 833: 827: 822: 819: 814: 809: 802: 799: 788: 787: 786: 784: 780: 779:inverse limit 776: 772: 768: 764: 760: 741: 736: 732: 728: 725: 720: 716: 711: 708: 705: 700: 696: 692: 689: 686: 683: 680: 677: 672: 668: 660: 659: 658: 656: 652: 648: 644: 640: 636: 613: 610: 603: 601: 596: 592: 591:adic topology 588: 584: 580: 577: 573: 570: 566: 560: 559:Adic topology 550: 548: 532: 527: 523: 514: 510: 506: 502: 499:, a filtered 498: 497:filtered ring 494: 490: 486: 482: 462: 458: 454: 451: 448: 436: 431: 427: 422: 412: 408: 404: 399: 395: 389: 381: 376: 372: 367: 363: 355: 352: 349: 345: 341: 336: 333: 330: 315: 311: 297: 293: 287: 282: 278: 273: 269: 263: 258: 255: 250: 244: 241: 231: 230: 229: 227: 226:inverse limit 207: 204: 201: 196: 192: 188: 185: 180: 176: 172: 169: 164: 160: 156: 153: 146: 145: 144: 143: 139: 138:abelian group 135: 132:Suppose that 125: 123: 120: 116: 112: 108: 104: 100: 99:Taylor series 97: 93: 89: 85: 81: 77: 73: 69: 65: 61: 57: 53: 49: 45: 41: 37: 30: 19: 3124: 3118: 3111:Gabber, Ofer 3077: 3056: 3026: 3014: 3002: 2991:. Retrieved 2987: 2978: 2954:Zariski ring 2925: 2921: 2832: 2828: 2793: 2787: 2674: 2665:-modules is 2662: 2588: 2584: 2580: 2573: 2565: 2412: 2408: 2404: 2400: 2396: 2392: 2388: 2318: 2314: 2310: 2292: 1673: 1326: 1322: 1314: 1313:is the ring 1210: 1206: 1198: 1194: 1185: 1129: 1127:The ring of 1075: 1073: 983: 979: 975: 973: 911: 907: 899: 897: 887:which is an 872: 866: 783:factor rings 774: 770: 766: 762: 758: 756: 654: 650: 649:, which are 646: 642: 599: 594: 586: 578: 571: 562: 505:vector space 492: 488: 484: 480: 478: 223: 133: 131: 114: 107:metric space 95: 91: 87: 83: 79: 64:localization 39: 33: 29:Completeness 2570:flat module 1738:plane curve 509:commutative 82:on a space 3147:Categories 3041:References 2993:2017-01-14 2298:Properties 893:local ring 142:filtration 103:completion 40:completion 2970:Citations 2920:for some 2877:… 2852:≃ 2763:^ 2746:^ 2737:≅ 2731:^ 2677:-algebra 2639:^ 2624:⊗ 2611:^ 2539:^ 2510:^ 2495:^ 2461:^ 2452:→ 2446:^ 2431:^ 2365:^ 2356:→ 2350:^ 2335:^ 2212:− 2173:− 2162:∞ 2147:∑ 1981:− 1785:− 1643:− 1627:… 1611:− 1557:↦ 1531:^ 1521:→ 1499:… 1384:… 1290:^ 1247:… 1097:^ 1029:⁡ 1024:← 1004:^ 953:∈ 946:for  828:⁡ 823:← 803:^ 709:⋯ 706:⊃ 693:⊃ 687:⊃ 452:≤ 405:≡ 353:≥ 346:∏ 342:∈ 334:≥ 321:¯ 264:⁡ 259:← 245:^ 208:⋯ 205:⊃ 189:⊃ 173:⊃ 3055:(1969). 2933:See also 1122:Examples 982:-module 773:.) The ( 761:∈ 641:of 0 in 485:additive 44:functors 3104:1322960 2403::  2313::  1201:be the 904:modules 875:. Thus 781:of the 600:maximal 60:modules 52:modules 3096:  3088:  3063:  2481:where 1680:scheme 651:nested 637:. The 501:module 483:is an 136:is an 2831:. If 2798:local 2667:exact 2572:over 2568:is a 1678:of a 1317:] of 1082:over 891:or a 602:ideal 585:) or 576:ideal 495:is a 109:with 105:of a 48:rings 3094:ISBN 3086:ISBN 3061:ISBN 2824:and 2399:and 2391:and 1918:and 1415:the 1213:and 1193:Let 974:The 511:and 58:and 50:and 38:, a 3129:doi 3125:332 2064:in 1321:in 1205:in 1118:. 1021:lim 820:lim 593:on 563:In 423:mod 256:lim 96:all 46:on 34:In 3149:: 3123:. 3117:. 3101:MR 3092:; 3080:. 3076:, 3051:; 2986:. 1197:= 1188:). 895:. 785:, 769:+ 657:: 549:. 228:: 124:. 3137:. 3131:: 3069:. 2996:. 2926:I 2922:n 2904:I 2900:/ 2896:] 2893:] 2888:n 2884:x 2880:, 2874:, 2869:1 2865:x 2861:[ 2858:[ 2855:K 2849:R 2833:R 2829:K 2810:m 2794:R 2769:. 2760:I 2753:/ 2743:R 2727:I 2723:/ 2719:R 2693:I 2689:/ 2685:R 2675:R 2663:R 2645:. 2636:R 2628:R 2620:M 2617:= 2608:M 2591:: 2585:R 2581:M 2576:. 2574:R 2566:R 2545:. 2536:R 2507:N 2501:, 2492:M 2467:, 2458:N 2443:M 2437:: 2428:f 2413:f 2409:N 2405:M 2401:f 2397:R 2393:N 2389:M 2371:. 2362:S 2347:R 2341:: 2332:f 2319:S 2315:R 2311:f 2278:. 2273:1 2270:+ 2267:n 2263:x 2256:) 2251:n 2247:4 2243:( 2238:2 2234:) 2230:! 2227:n 2224:( 2221:) 2218:n 2215:2 2209:1 2206:( 2201:! 2198:) 2195:n 2192:2 2189:( 2184:n 2180:) 2176:1 2170:( 2157:0 2154:= 2151:n 2143:= 2138:x 2135:+ 2132:1 2127:x 2124:= 2121:u 2098:. 2095:] 2092:] 2089:y 2086:, 2083:x 2080:[ 2077:[ 2073:C 2052:) 2049:x 2046:+ 2043:1 2040:( 2035:2 2031:x 2010:u 1990:) 1987:) 1984:u 1978:y 1975:( 1972:) 1969:u 1966:+ 1963:y 1960:( 1957:( 1953:/ 1949:] 1946:] 1943:y 1940:, 1937:x 1934:[ 1931:[ 1927:C 1906:) 1903:y 1900:x 1897:( 1893:/ 1889:] 1886:] 1883:y 1880:, 1877:x 1874:[ 1871:[ 1867:C 1846:) 1843:y 1840:, 1837:x 1834:( 1813:) 1810:) 1807:x 1804:+ 1801:1 1798:( 1793:2 1789:x 1780:2 1776:y 1772:( 1768:/ 1764:] 1761:y 1758:, 1755:x 1752:[ 1748:C 1724:) 1721:y 1718:x 1715:( 1711:/ 1707:] 1704:y 1701:, 1698:x 1695:[ 1691:C 1659:. 1656:) 1651:n 1647:f 1638:n 1634:x 1630:, 1624:, 1619:1 1615:f 1606:1 1602:x 1598:( 1565:i 1561:f 1552:i 1548:x 1538:I 1528:R 1518:] 1515:] 1510:n 1506:x 1502:, 1496:, 1491:1 1487:x 1483:[ 1480:[ 1477:R 1471:{ 1443:R 1423:I 1403:, 1400:) 1395:n 1391:f 1387:, 1381:, 1376:1 1372:f 1368:( 1365:= 1362:I 1342:R 1329:. 1327:K 1323:n 1315:K 1298:m 1287:R 1263:) 1258:n 1254:x 1250:, 1244:, 1239:1 1235:x 1231:( 1228:= 1223:m 1211:K 1207:n 1199:K 1195:R 1186:p 1171:Z 1148:p 1143:Z 1130:p 1104:I 1094:R 1076:R 1059:. 1056:) 1053:M 1048:n 1044:I 1039:/ 1035:M 1032:( 1016:= 1011:I 1001:M 984:M 980:R 976:I 959:. 956:M 950:x 941:M 936:n 932:I 928:+ 925:x 912:M 908:I 902:- 900:R 877:π 873:I 869:π 852:) 847:n 843:I 838:/ 834:R 831:( 815:= 810:I 800:R 775:I 771:I 767:r 763:R 759:r 742:. 737:n 733:I 729:= 726:R 721:n 717:F 712:, 701:2 697:I 690:I 684:R 681:= 678:R 673:0 669:F 655:R 647:I 643:R 619:m 614:= 611:I 595:R 589:- 587:I 579:I 572:R 533:E 528:i 524:F 493:E 489:E 481:E 463:. 459:} 455:j 449:i 440:) 437:E 432:i 428:F 420:( 413:j 409:a 400:i 396:a 390:| 385:) 382:E 377:n 373:F 368:/ 364:E 361:( 356:0 350:n 337:0 331:n 327:) 316:n 312:a 306:( 298:{ 294:= 291:) 288:E 283:n 279:F 274:/ 270:E 267:( 251:= 242:E 202:E 197:2 193:F 186:E 181:1 177:F 170:E 165:0 161:F 157:= 154:E 134:E 115:R 92:X 84:X 80:R 31:. 20:)

Index

Completion (algebra)
Completeness
abstract algebra
functors
rings
modules
topological rings
modules
localization
commutative rings
Hensel's lemma
algebraic geometry
Taylor series
completion
metric space
Cauchy sequences
non-Archimedean
absolute value
abelian group
filtration
inverse limit
filtered ring
module
vector space
commutative
noncommutative rings
complete topological ring
Adic topology
commutative algebra
commutative ring

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