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Local ring

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872: 614: 1165:. We are only interested in the behavior of these functions near 0 (their "local behavior") and we will therefore identify two functions if they agree on some (possibly very small) open interval around 0. This identification defines an 249:, one does not have to distinguish between left, right and two-sided ideals: a commutative ring is local if and only if it has a unique maximal ideal. Before about 1960 many authors required that a local ring be (left and right) 192:. The third of the properties listed above says that the set of non-units in a local ring forms a (proper) ideal, necessarily contained in the Jacobson radical. The fourth property can be paraphrased as follows: a ring 2150: 1255:
With this characterization, it is clear that the sum of any two non-invertible germs is again non-invertible, and we have a commutative local ring. The maximal ideal of this ring consists precisely of those germs
2324: 2345:(which is equal to the unique maximal left ideal and also to the unique maximal right ideal) consists precisely of the non-units of the ring; furthermore, it is the unique maximal two-sided ideal of 1722: 328: 459: 686: 2625: 2539: 464: 1827: 2577: 401: 1372: 1120: 1094: 1024: 2176: 2208: 1885: 1854: 2234: 1783: 1050: 999: 1070: 973: 953: 933: 688:, is local. Its unique maximal ideal consists of all elements that are not invertible. In other words, it consists of all elements with constant term zero. 184:
If a finite sum is a unit, then it has a term that is a unit (this says in particular that the empty sum cannot be a unit, so it implies 1 ≠ 0).
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The 2 by 2 matrices over a field, for example, has unique maximal ideal {0}, but it has multiple maximal right and left ideals.
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If these properties hold, then the unique maximal left ideal coincides with the unique maximal right ideal and with the ring's
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denominator is local; its maximal ideal consists of the fractions with even numerator and odd denominator. It is the integers
2834: 729:) is local with maximal ideal consisting of the classes of polynomials with constant term belonging to the maximal ideal of 46:
that are comparatively simple, and serve to describe what is called "local behaviour", in the sense of functions defined on
2897: 1667: 2812: 291: 2349:. However, in the non-commutative case, having a unique maximal two-sided ideal is not equivalent to being local. 406: 1177:
of real-valued continuous functions at 0". These germs can be added and multiplied and form a commutative ring.
619: 609:{\textstyle (\sum _{i=0}^{\infty }a_{i}x^{i})(\sum _{i=0}^{\infty }b_{i}x^{i})=\sum _{i=0}^{\infty }c_{i}x^{i}} 2586: 2500: 1788: 2544: 2019:. These are precisely the ring homomorphisms that are continuous with respect to the given topologies on 2482: 1911: 1562: 369: 1355: 1103: 1077: 1007: 2850: 1915: 1279: 1270:
Exactly the same arguments work for the ring of germs of continuous real-valued functions on any
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To see that this ring of germs is local, we need to characterize its invertible elements. A germ
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at a given point. All these rings are therefore local. These examples help to explain why
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be the ring of germs of infinitely differentiable functions at 0 in the real line and
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over a local ring is local; the maximal ideal consists of those power series with
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is a concept without a simple definition. It is replaced by using valuations.
2886: 2693: 1941: 1907: 719: 696: 135: 1914:, again a local ring. Complete Noetherian local rings are classified by the 1530:
over some other rings. Specifically, if the endomorphism ring of the module
2774: 707: 2631:, the conclusion is that the only rings Morita equivalent to a local ring 830:
in this localization; that is, the maximal ideal consists of all elements
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More generally, a nonzero ring in which every element is either a unit or
2466: 2406: 2145:{\displaystyle \mathbb {C} /(x^{3})\to \mathbb {C} /(x^{3},x^{2}y,y^{4})} 804: 86: 35: 31: 1416:
has dimension 2 or more there is a difficulty that is seen this way: if
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In practice, a commutative local ring often arises as the result of the
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To motivate the name "local" for these rings, we consider real-valued
285:) are local rings, since {0} is the only maximal ideal in these rings. 1162: 757: 349: 2877: 2717: 1751:, and, as such, the "Noetherian" assumption is crucial. Indeed, let 1312:
Local rings play a major role in valuation theory. By definition, a
2800: 51: 1344:. Any such subring will be a local ring. For example, the ring of 2807:. Graduate Texts in Mathematics (2nd ed.). Springer-Verlag. 1576: 197: 105: 2698:"Foundations of a General Theory of Birational Correspondences" 1198:, then by continuity there is an open interval around 0 where 2319:{\displaystyle \mathbb {C} /(x^{3})\to \mathbb {C} /(x^{2})} 1550:
and is indecomposable, then its endomorphism ring is local.
1294:, the generalizations of varieties, are defined as special 127:
if it has any one of the following equivalent properties:
341:). The unique maximal ideal consists of all multiples of 253:, and (possibly non-Noetherian) local rings were called 2579:. Since every ring Morita equivalent to the local ring 2236:. Another example of a local ring morphism is given by 1352:
denominator (mentioned above) is a valuation ring in
826:
is local; the maximal ideal is the ideal generated by
622: 467: 409: 2589: 2547: 2503: 2242: 2216: 2184: 2158: 2033: 1866: 1835: 1791: 1765: 1670: 1358: 1106: 1080: 1058: 1032: 1010: 981: 961: 941: 912: 372: 294: 111: 1717:{\displaystyle \bigcap _{i=1}^{\infty }m^{i}=\{0\}} 257:. In this article this requirement is not imposed. 2619: 2571: 2533: 2473:. This has an interesting consequence in terms of 2318: 2228: 2202: 2170: 2144: 1879: 1848: 1821: 1777: 1716: 1366: 1114: 1088: 1064: 1044: 1018: 993: 967: 947: 927: 680: 608: 453: 395: 322: 1890:As for any topological ring, one can ask whether 2884: 1945:of the local ring or residue field of the point 778:Nonzero quotient rings of local rings are local. 1518:Non-commutative local rings arise naturally as 196:is local if and only if there do not exist two 27:(Mathematical) ring with a unique maximal ideal 2711:(3). American Mathematical Society: 490–542 . 2658:(1938). "Dimensionstheorie in Stellenringen". 323:{\displaystyle \mathbb {Z} /p^{n}\mathbb {Z} } 1592: 92:The concept of local rings was introduced by 1925:is the local ring of a scheme at some point 1711: 1705: 1626:in a natural way if one takes the powers of 710:over any field is local. More generally, if 454:{\textstyle \sum _{i=0}^{\infty }a_{i}x^{i}} 2541:is isomorphic to the full ring of matrices 2635:are (isomorphic to) the matrix rings over 2027:. For example, consider the ring morphism 1282:at a given point, or the ring of germs of 1274:at a given point, or the ring of germs of 1202:is non-zero, and we can form the function 1026:is not local since it has a maximal ideal 681:{\textstyle c_{n}=\sum _{i+j=n}a_{i}b_{j}} 2716: 2282: 2244: 2073: 2035: 1360: 1225:gives rise to a germ, and the product of 1108: 1082: 1012: 374: 316: 296: 2821: 1473:. Considering a simple example, such as 1404:we could try to define a valuation ring 1385:, we may look for local rings in it. If 2692: 1921:In algebraic geometry, especially when 1001:are non-units, but their sum is a unit. 14: 2885: 2805:A first course in noncommutative rings 2686: 2497:, and hence the ring of endomorphisms 1743:. The theorem is a consequence of the 699:in the maximal ideal of the base ring. 355:An important class of local rings are 2829:. Vol. 2 (2nd ed.). Dover. 2748: 2654: 2620:{\displaystyle \mathrm {End} _{R}(P)} 2534:{\displaystyle \mathrm {End} _{R}(P)} 1389:were indeed the function field of an 1324:such that for every non-zero element 403:, whose elements are infinite series 2648: 1822:{\displaystyle e^{-{1 \over x^{2}}}} 866: 2799: 2572:{\displaystyle \mathrm {M} _{n}(R)} 2442:is again local, with maximal ideal 1910:); if it is not, one considers its 1597: 1301: 461:where multiplications are given by 24: 2598: 2595: 2592: 2550: 2512: 2509: 2506: 1687: 1513: 1233:is invertible, then there is some 1130:are distinct prime numbers. Both ( 581: 534: 487: 426: 204:) (left) ideals, where two ideals 25: 2909: 2878:The philosophy behind local rings 2871: 2493:is isomorphic to the free module 1860:, since that function divided by 151:1 ≠ 0 and the sum of any two non- 148:has a unique maximal right ideal. 112:Definition and first consequences 2360:, the following are equivalent: 1142: 870: 737:to invert all other polynomials 718:is a positive integer, then the 2329: 1229:is equal to 1. (Conversely, if 1221:on this interval. The function 862: 2781: 2767: 2742: 2739:Lam (2001), p. 295, Thm. 19.1. 2733: 2614: 2608: 2566: 2560: 2528: 2522: 2313: 2300: 2292: 2286: 2278: 2275: 2262: 2254: 2248: 2223: 2217: 2197: 2185: 2162: 2139: 2097: 2089: 2077: 2069: 2066: 2053: 2045: 2039: 1772: 1766: 1039: 1033: 922: 916: 691:More generally, every ring of 559: 515: 512: 468: 390: 387: 381: 378: 13: 1: 2793: 1614:for a commutative local ring 1381:, which may or may not be a 1184:is invertible if and only if 748:is a field, then elements of 396:{\displaystyle \mathbb {C} ]} 1729:Krull's intersection theorem 1622:. Every such ring becomes a 1542:; conversely, if the module 1367:{\displaystyle \mathbb {Q} } 1115:{\displaystyle \mathbb {Z} } 1089:{\displaystyle \mathbb {Z} } 1019:{\displaystyle \mathbb {Z} } 7: 2844: 271: 10: 2914: 2898:Localization (mathematics) 2430:is any two-sided ideal in 2171:{\displaystyle x\mapsto x} 1785:. Then a nonzero function 1593:Some facts and definitions 1424:are rational functions on 1408:of functions "defined at" 1305: 1146: 1138:) are maximal ideals here. 796:More generally, given any 18:Krull intersection theorem 2672:10.1515/crll.1938.179.204 1173:are what are called the " 764:. (The dual numbers over 58:examined at a particular 2642: 1976:are local rings, then a 1488:approached along a line 357:discrete valuation rings 260:A local ring that is an 2851:Discrete valuation ring 2434:, then the factor ring 1978:local ring homomorphism 1916:Cohen structure theorem 1731:), and it follows that 1280:differentiable manifold 768:correspond to the case 361:principal ideal domains 96:in 1938 under the name 56:algebraic number fields 34:, more specifically in 2705:Trans. Amer. Math. Soc 2621: 2573: 2535: 2320: 2230: 2204: 2172: 2146: 1881: 1850: 1823: 1779: 1718: 1691: 1396:, then for each point 1368: 1116: 1090: 1066: 1046: 1020: 995: 969: 949: 929: 733:, since one can use a 682: 610: 585: 538: 491: 455: 430: 397: 324: 83:localization of a ring 74:local rings and their 2866:Gorenstein local ring 2755:mathworld.wolfram.com 2660:J. Reine Angew. Math. 2622: 2574: 2536: 2465:over a local ring is 2321: 2231: 2205: 2203:{\displaystyle (x,y)} 2173: 2147: 1882: 1880:{\displaystyle x^{n}} 1851: 1849:{\displaystyle m^{n}} 1824: 1780: 1759:be the maximal ideal 1719: 1671: 1369: 1296:locally ringed spaces 1117: 1091: 1067: 1047: 1021: 1004:The ring of integers 996: 970: 950: 930: 683: 611: 565: 518: 471: 456: 410: 398: 325: 2587: 2545: 2501: 2240: 2214: 2182: 2156: 2031: 1864: 1833: 1789: 1763: 1739:-adic topology is a 1668: 1356: 1167:equivalence relation 1155:continuous functions 1104: 1078: 1056: 1030: 1008: 979: 959: 955:is not local, since 939: 910: 714:is a local ring and 620: 465: 407: 370: 363:that are not fields. 292: 100:. The English term 2749:Weisstein, Eric W. 2405:is local, then the 2373:has a right inverse 2229:{\displaystyle (x)} 1778:{\displaystyle (x)} 1618:with maximal ideal 1308:Valuation (algebra) 1171:equivalence classes 1045:{\displaystyle (p)} 994:{\displaystyle 1-x} 905:ring of polynomials 693:formal power series 68:commutative algebra 48:algebraic varieties 2617: 2569: 2531: 2483:finitely generated 2475:Morita equivalence 2367:has a left inverse 2356:of the local ring 2316: 2226: 2200: 2178:. The preimage of 2168: 2142: 2005:with the property 1877: 1846: 1819: 1775: 1714: 1634:of 0. This is the 1526:decompositions of 1520:endomorphism rings 1503:one sees that the 1467:indeterminate form 1364: 1332:, at least one of 1284:rational functions 1149:Germ (mathematics) 1112: 1086: 1062: 1042: 1016: 991: 965: 945: 925: 882:. You can help by 678: 657: 606: 451: 393: 359:, which are local 320: 166:is any element of 2836:978-0-486-47187-7 2463:projective module 1990:ring homomorphism 1887:is still smooth. 1815: 1661:local ring, then 1657:is a commutative 1632:neighborhood base 1412:. In cases where 1391:algebraic variety 1288:algebraic variety 1278:functions on any 1272:topological space 1191:. The reason: if 1065:{\displaystyle p} 968:{\displaystyle x} 948:{\displaystyle K} 928:{\displaystyle K} 900: 899: 636: 330:is a local ring ( 255:quasi-local rings 247:commutative rings 66:is the branch of 16:(Redirected from 2905: 2840: 2823:Jacobson, Nathan 2818: 2788: 2785: 2779: 2778: 2771: 2765: 2764: 2762: 2761: 2746: 2740: 2737: 2731: 2730: 2720: 2702: 2690: 2684: 2683: 2652: 2626: 2624: 2623: 2618: 2607: 2606: 2601: 2578: 2576: 2575: 2570: 2559: 2558: 2553: 2540: 2538: 2537: 2532: 2521: 2520: 2515: 2471:Nakayama's lemma 2459:Irving Kaplansky 2429: 2404: 2341:of a local ring 2336:Jacobson radical 2325: 2323: 2322: 2317: 2312: 2311: 2299: 2285: 2274: 2273: 2261: 2247: 2235: 2233: 2232: 2227: 2209: 2207: 2206: 2201: 2177: 2175: 2174: 2169: 2151: 2149: 2148: 2143: 2138: 2137: 2122: 2121: 2109: 2108: 2096: 2076: 2065: 2064: 2052: 2038: 2018: 2004: 1975: 1963: 1938: 1901: 1886: 1884: 1883: 1878: 1876: 1875: 1855: 1853: 1852: 1847: 1845: 1844: 1828: 1826: 1825: 1820: 1818: 1817: 1816: 1814: 1813: 1801: 1784: 1782: 1781: 1776: 1749:Nakayama's lemma 1745:Artin–Rees lemma 1723: 1721: 1720: 1715: 1701: 1700: 1690: 1685: 1656: 1624:topological ring 1613: 1598:Commutative case 1570: 1522:in the study of 1373: 1371: 1370: 1365: 1363: 1346:rational numbers 1302:Valuation theory 1266: 1251: 1220: 1197: 1190: 1161:around 0 of the 1157:defined on some 1121: 1119: 1118: 1113: 1111: 1095: 1093: 1092: 1087: 1085: 1071: 1069: 1068: 1063: 1052:for every prime 1051: 1049: 1048: 1043: 1025: 1023: 1022: 1017: 1015: 1000: 998: 997: 992: 974: 972: 971: 966: 954: 952: 951: 946: 934: 932: 931: 926: 895: 892: 874: 867: 798:commutative ring 783:rational numbers 774: 735:geometric series 687: 685: 684: 679: 677: 676: 667: 666: 656: 632: 631: 615: 613: 612: 607: 605: 604: 595: 594: 584: 579: 558: 557: 548: 547: 537: 532: 511: 510: 501: 500: 490: 485: 460: 458: 457: 452: 450: 449: 440: 439: 429: 424: 402: 400: 399: 394: 377: 352:is a local ring. 344: 340: 333: 329: 327: 326: 321: 319: 314: 313: 304: 299: 241: 190:Jacobson radical 180: 21: 2913: 2912: 2908: 2907: 2906: 2904: 2903: 2902: 2883: 2882: 2874: 2856:Semi-local ring 2847: 2837: 2815: 2796: 2791: 2786: 2782: 2773: 2772: 2768: 2759: 2757: 2747: 2743: 2738: 2734: 2718:10.2307/1990215 2700: 2691: 2687: 2656:Krull, Wolfgang 2653: 2649: 2645: 2602: 2591: 2590: 2588: 2585: 2584: 2583:is of the form 2554: 2549: 2548: 2546: 2543: 2542: 2516: 2505: 2504: 2502: 2499: 2498: 2421: 2394: 2352:For an element 2332: 2307: 2303: 2295: 2281: 2269: 2265: 2257: 2243: 2241: 2238: 2237: 2215: 2212: 2211: 2183: 2180: 2179: 2157: 2154: 2153: 2133: 2129: 2117: 2113: 2104: 2100: 2092: 2072: 2060: 2056: 2048: 2034: 2032: 2029: 2028: 2006: 1992: 1965: 1953: 1930: 1891: 1871: 1867: 1865: 1862: 1861: 1840: 1836: 1834: 1831: 1830: 1809: 1805: 1800: 1796: 1792: 1790: 1787: 1786: 1764: 1761: 1760: 1741:Hausdorff space 1696: 1692: 1686: 1675: 1669: 1666: 1665: 1646: 1603: 1600: 1595: 1565: 1534:is local, then 1516: 1514:Non-commutative 1359: 1357: 1354: 1353: 1310: 1304: 1261: 1246: 1245:(0) = 1, hence 1203: 1192: 1185: 1151: 1145: 1107: 1105: 1102: 1101: 1081: 1079: 1076: 1075: 1057: 1054: 1053: 1031: 1028: 1027: 1011: 1009: 1006: 1005: 980: 977: 976: 960: 957: 956: 940: 937: 936: 911: 908: 907: 896: 890: 887: 880:needs expansion 865: 769: 702:Similarly, the 672: 668: 662: 658: 640: 627: 623: 621: 618: 617: 600: 596: 590: 586: 580: 569: 553: 549: 543: 539: 533: 522: 506: 502: 496: 492: 486: 475: 466: 463: 462: 445: 441: 435: 431: 425: 414: 408: 405: 404: 373: 371: 368: 367: 342: 335: 331: 315: 309: 305: 300: 295: 293: 290: 289: 274: 262:integral domain 245:In the case of 240: 233: 223: 217: 210: 175: 114: 28: 23: 22: 15: 12: 11: 5: 2911: 2901: 2900: 2895: 2881: 2880: 2873: 2872:External links 2870: 2869: 2868: 2863: 2861:Valuation ring 2858: 2853: 2846: 2843: 2842: 2841: 2835: 2819: 2813: 2795: 2792: 2790: 2789: 2780: 2766: 2741: 2732: 2694:Zariski, Oscar 2685: 2646: 2644: 2641: 2616: 2613: 2610: 2605: 2600: 2597: 2594: 2568: 2565: 2562: 2557: 2552: 2530: 2527: 2524: 2519: 2514: 2511: 2508: 2461:says that any 2391: 2390: 2380: 2374: 2368: 2331: 2328: 2315: 2310: 2306: 2302: 2298: 2294: 2291: 2288: 2284: 2280: 2277: 2272: 2268: 2264: 2260: 2256: 2253: 2250: 2246: 2225: 2222: 2219: 2199: 2196: 2193: 2190: 2187: 2167: 2164: 2161: 2141: 2136: 2132: 2128: 2125: 2120: 2116: 2112: 2107: 2103: 2099: 2095: 2091: 2088: 2085: 2082: 2079: 2075: 2071: 2068: 2063: 2059: 2055: 2051: 2047: 2044: 2041: 2037: 1939:is called the 1874: 1870: 1843: 1839: 1812: 1808: 1804: 1799: 1795: 1774: 1771: 1768: 1747:together with 1725: 1724: 1713: 1710: 1707: 1704: 1699: 1695: 1689: 1684: 1681: 1678: 1674: 1639:-adic topology 1602:We also write 1599: 1596: 1594: 1591: 1563:characteristic 1540:indecomposable 1515: 1512: 1501: 1500: 1486: 1485: 1463: 1462: 1449: 1448: 1383:function field 1377:Given a field 1362: 1314:valuation ring 1306:Main article: 1303: 1300: 1276:differentiable 1147:Main article: 1144: 1141: 1140: 1139: 1110: 1084: 1073: 1061: 1041: 1038: 1035: 1014: 1002: 990: 987: 984: 964: 944: 924: 921: 918: 915: 898: 897: 877: 875: 864: 861: 860: 859: 794: 779: 776: 700: 689: 675: 671: 665: 661: 655: 652: 649: 646: 643: 639: 635: 630: 626: 603: 599: 593: 589: 583: 578: 575: 572: 568: 564: 561: 556: 552: 546: 542: 536: 531: 528: 525: 521: 517: 514: 509: 505: 499: 495: 489: 484: 481: 478: 474: 470: 448: 444: 438: 434: 428: 423: 420: 417: 413: 392: 389: 386: 383: 380: 376: 364: 353: 346: 318: 312: 308: 303: 298: 286: 273: 270: 238: 231: 215: 208: 186: 185: 182: 160: 159:is a non-unit. 149: 143: 113: 110: 94:Wolfgang Krull 26: 9: 6: 4: 3: 2: 2910: 2899: 2896: 2894: 2891: 2890: 2888: 2879: 2876: 2875: 2867: 2864: 2862: 2859: 2857: 2854: 2852: 2849: 2848: 2838: 2832: 2828: 2827:Basic algebra 2824: 2820: 2816: 2814:0-387-95183-0 2810: 2806: 2802: 2798: 2797: 2784: 2776: 2770: 2756: 2752: 2745: 2736: 2728: 2724: 2719: 2714: 2710: 2706: 2699: 2695: 2689: 2681: 2677: 2673: 2669: 2665: 2662:(in German). 2661: 2657: 2651: 2647: 2640: 2638: 2634: 2630: 2611: 2603: 2582: 2563: 2555: 2525: 2517: 2496: 2492: 2489:module, then 2488: 2484: 2480: 2477:. Namely, if 2476: 2472: 2468: 2464: 2460: 2456: 2451: 2449: 2445: 2441: 2437: 2433: 2428: 2424: 2419: 2415: 2411: 2408: 2402: 2398: 2388: 2384: 2381: 2379:is invertible 2378: 2375: 2372: 2369: 2366: 2363: 2362: 2361: 2359: 2355: 2350: 2348: 2344: 2340: 2337: 2327: 2308: 2304: 2296: 2289: 2270: 2266: 2258: 2251: 2220: 2194: 2191: 2188: 2165: 2159: 2134: 2130: 2126: 2123: 2118: 2114: 2110: 2105: 2101: 2093: 2086: 2083: 2080: 2061: 2057: 2049: 2042: 2026: 2022: 2017: 2013: 2009: 2003: 1999: 1995: 1991: 1987: 1983: 1979: 1973: 1969: 1961: 1957: 1950: 1948: 1944: 1943: 1942:residue field 1937: 1933: 1928: 1924: 1919: 1917: 1913: 1909: 1908:uniform space 1905: 1899: 1895: 1888: 1872: 1868: 1859: 1841: 1837: 1810: 1806: 1802: 1797: 1793: 1769: 1758: 1754: 1750: 1746: 1742: 1738: 1734: 1730: 1708: 1702: 1697: 1693: 1682: 1679: 1676: 1672: 1664: 1663: 1662: 1660: 1654: 1650: 1644: 1640: 1638: 1633: 1629: 1625: 1621: 1617: 1611: 1607: 1590: 1588: 1585: 1584:group algebra 1581: 1579: 1574: 1568: 1564: 1560: 1556: 1551: 1549: 1545: 1541: 1537: 1533: 1529: 1525: 1521: 1511: 1509: 1506: 1498: 1494: 1491: 1490: 1489: 1483: 1479: 1476: 1475: 1474: 1472: 1468: 1461: 1457: 1454: 1453: 1452: 1451:the function 1446: 1442: 1438: 1434: 1431: 1430: 1429: 1427: 1423: 1419: 1415: 1411: 1407: 1403: 1399: 1395: 1392: 1388: 1384: 1380: 1375: 1351: 1347: 1343: 1339: 1335: 1331: 1327: 1323: 1320:is a subring 1319: 1315: 1309: 1299: 1297: 1293: 1289: 1285: 1281: 1277: 1273: 1268: 1264: 1259: 1253: 1249: 1244: 1240: 1236: 1232: 1228: 1224: 1218: 1214: 1210: 1206: 1201: 1195: 1188: 1183: 1178: 1176: 1172: 1168: 1164: 1160: 1159:open interval 1156: 1150: 1143:Ring of germs 1137: 1133: 1129: 1125: 1099: 1074: 1059: 1036: 1003: 988: 985: 982: 962: 942: 935:over a field 919: 913: 906: 902: 901: 894: 885: 881: 878:This section 876: 873: 869: 868: 857: 853: 849: 845: 841: 837: 833: 829: 825: 821: 817: 813: 809: 806: 802: 799: 795: 792: 788: 784: 780: 777: 772: 767: 763: 759: 756:) are either 755: 751: 747: 743: 740: 736: 732: 728: 724: 721: 720:quotient ring 717: 713: 709: 705: 701: 698: 697:constant term 694: 690: 673: 669: 663: 659: 653: 650: 647: 644: 641: 637: 633: 628: 624: 601: 597: 591: 587: 576: 573: 570: 566: 562: 554: 550: 544: 540: 529: 526: 523: 519: 507: 503: 497: 493: 482: 479: 476: 472: 446: 442: 436: 432: 421: 418: 415: 411: 384: 365: 362: 358: 354: 351: 347: 338: 310: 306: 301: 287: 284: 280: 276: 275: 269: 267: 263: 258: 256: 252: 248: 243: 237: 230: 226: 221: 214: 207: 203: 199: 195: 191: 183: 179: 173: 169: 165: 162:1 ≠ 0 and if 161: 158: 154: 150: 147: 144: 141: 137: 134:has a unique 133: 130: 129: 128: 126: 122: 119: 109: 107: 103: 99: 95: 90: 88: 84: 79: 77: 73: 70:that studies 69: 65: 64:Local algebra 61: 57: 53: 49: 45: 41: 37: 33: 19: 2826: 2804: 2783: 2769: 2758:. Retrieved 2754: 2751:"Local Ring" 2744: 2735: 2708: 2704: 2696:(May 1943). 2688: 2666:(179): 204. 2663: 2659: 2650: 2636: 2632: 2628: 2580: 2494: 2490: 2486: 2478: 2455:deep theorem 2452: 2447: 2443: 2439: 2435: 2431: 2426: 2422: 2413: 2409: 2400: 2396: 2392: 2386: 2382: 2376: 2370: 2364: 2357: 2353: 2351: 2346: 2342: 2338: 2333: 2330:General case 2024: 2020: 2015: 2011: 2007: 2001: 1997: 1993: 1985: 1981: 1977: 1971: 1967: 1959: 1955: 1951: 1946: 1940: 1935: 1931: 1926: 1922: 1920: 1897: 1893: 1889: 1857: 1756: 1752: 1736: 1732: 1728: 1726: 1652: 1648: 1642: 1636: 1627: 1619: 1615: 1609: 1605: 1601: 1586: 1577: 1575:is a finite 1572: 1566: 1554: 1552: 1543: 1535: 1531: 1517: 1507: 1504: 1502: 1496: 1492: 1487: 1481: 1477: 1470: 1464: 1459: 1455: 1450: 1444: 1440: 1436: 1432: 1425: 1421: 1417: 1413: 1409: 1405: 1401: 1397: 1393: 1386: 1378: 1376: 1341: 1337: 1333: 1329: 1325: 1321: 1317: 1311: 1269: 1262: 1257: 1254: 1247: 1242: 1238: 1234: 1230: 1226: 1222: 1216: 1212: 1208: 1204: 1199: 1193: 1186: 1181: 1179: 1152: 1135: 1131: 1127: 1123: 1097: 891:January 2022 888: 884:adding to it 879: 863:Non-examples 855: 851: 847: 843: 839: 835: 831: 827: 823: 819: 816:localization 811: 807: 800: 781:The ring of 770: 765: 753: 749: 745: 741: 730: 726: 722: 715: 711: 708:dual numbers 336: 266:local domain 265: 264:is called a 259: 254: 244: 235: 228: 224: 219: 212: 205: 193: 187: 177: 171: 167: 163: 156: 145: 131: 124: 120: 115: 101: 98:Stellenringe 97: 91: 80: 63: 62:, or prime. 42:are certain 39: 29: 2893:Ring theory 2627:for such a 2485:projective 2407:factor ring 1829:belongs to 1582:, then the 1546:has finite 1316:of a field 805:prime ideal 283:skew fields 218:are called 87:prime ideal 72:commutative 40:local rings 36:ring theory 32:mathematics 2887:Categories 2794:References 2775:"Tag 07BI" 2760:2024-08-26 2418:skew field 2385:is not in 1912:completion 1659:Noetherian 1589:is local. 1524:direct sum 1237:such that 1169:, and the 762:invertible 616:such that 251:Noetherian 181:is a unit. 176:1 − 125:local ring 104:is due to 102:local ring 2801:Lam, T.Y. 2680:115691729 2279:→ 2163:↦ 2070:→ 1798:− 1735:with the 1688:∞ 1673:⋂ 1163:real line 986:− 791:localized 758:nilpotent 638:∑ 582:∞ 567:∑ 535:∞ 520:∑ 488:∞ 473:∑ 427:∞ 412:∑ 366:The ring 350:nilpotent 288:The ring 202:principal 52:manifolds 2845:See also 2825:(2009). 2803:(2001). 2152:sending 1996: : 1904:complete 1856:for any 1505:value at 1122:, where 803:and any 272:Examples 200:proper ( 54:, or of 2727:1990215 1528:modules 1292:schemes 1286:on any 1265:(0) = 0 1250:(0) ≠ 0 1196:(0) ≠ 0 1189:(0) ≠ 0 1134:) and ( 704:algebra 334:prime, 220:coprime 198:coprime 170:, then 136:maximal 106:Zariski 76:modules 2833:  2811:  2725:  2678:  1906:(as a 1580:-group 1569:> 0 1548:length 1465:is an 1447:) = 0, 1340:is in 1211:) = 1/ 814:, the 739:modulo 279:fields 2723:JSTOR 2701:(PDF) 2676:S2CID 2643:Notes 2481:is a 2420:. If 2416:is a 1988:is a 1980:from 1645:. If 1630:as a 1559:field 1557:is a 1428:with 1348:with 1260:with 1175:germs 838:with 793:at 2. 785:with 744:. If 281:(and 153:units 140:ideal 138:left 123:is a 85:at a 60:place 44:rings 2831:ISBN 2809:ISBN 2664:1938 2467:free 2334:The 2023:and 2014:) ⊆ 1964:and 1571:and 1439:) = 1420:and 1336:and 1126:and 975:and 903:The 846:and 277:All 118:ring 2713:doi 2668:doi 2457:by 2393:If 2210:is 1984:to 1952:If 1902:is 1641:on 1561:of 1553:If 1538:is 1469:at 1400:of 1350:odd 1328:of 1252:.) 1241:(0) 886:. 822:at 818:of 810:of 787:odd 773:= 2 760:or 706:of 339:≥ 1 222:if 174:or 155:in 50:or 30:In 2889:: 2753:. 2721:. 2709:53 2707:. 2703:. 2674:. 2639:. 2453:A 2450:. 2425:≠ 2399:, 2326:. 2000:→ 1970:, 1958:, 1949:. 1934:/ 1929:, 1918:. 1896:, 1651:, 1608:, 1587:kG 1497:tX 1495:= 1374:. 1298:. 1267:. 1227:fg 1098:pq 1096:/( 854:- 850:∈ 842:∈ 775:.) 752:/( 725:/( 268:. 242:. 234:+ 227:= 211:, 116:A 108:. 89:. 78:. 38:, 2839:. 2817:. 2777:. 2763:. 2729:. 2715:: 2682:. 2670:: 2637:R 2633:R 2629:P 2615:) 2612:P 2609:( 2604:R 2599:d 2596:n 2593:E 2581:R 2567:) 2564:R 2561:( 2556:n 2551:M 2529:) 2526:P 2523:( 2518:R 2513:d 2510:n 2507:E 2495:R 2491:P 2487:R 2479:P 2448:J 2446:/ 2444:m 2440:J 2438:/ 2436:R 2432:R 2427:R 2423:J 2414:m 2412:/ 2410:R 2403:) 2401:m 2397:R 2395:( 2389:. 2387:m 2383:x 2377:x 2371:x 2365:x 2358:R 2354:x 2347:R 2343:R 2339:m 2314:) 2309:2 2305:x 2301:( 2297:/ 2293:] 2290:x 2287:[ 2283:C 2276:) 2271:3 2267:x 2263:( 2259:/ 2255:] 2252:x 2249:[ 2245:C 2224:) 2221:x 2218:( 2198:) 2195:y 2192:, 2189:x 2186:( 2166:x 2160:x 2140:) 2135:4 2131:y 2127:, 2124:y 2119:2 2115:x 2111:, 2106:3 2102:x 2098:( 2094:/ 2090:] 2087:y 2084:, 2081:x 2078:[ 2074:C 2067:) 2062:3 2058:x 2054:( 2050:/ 2046:] 2043:x 2040:[ 2036:C 2025:S 2021:R 2016:n 2012:m 2010:( 2008:f 2002:S 1998:R 1994:f 1986:S 1982:R 1974:) 1972:n 1968:S 1966:( 1962:) 1960:m 1956:R 1954:( 1947:P 1936:m 1932:R 1927:P 1923:R 1900:) 1898:m 1894:R 1892:( 1873:n 1869:x 1858:n 1842:n 1838:m 1811:2 1807:x 1803:1 1794:e 1773:) 1770:x 1767:( 1757:m 1753:R 1737:m 1733:R 1727:( 1712:} 1709:0 1706:{ 1703:= 1698:i 1694:m 1683:1 1680:= 1677:i 1655:) 1653:m 1649:R 1647:( 1643:R 1637:m 1628:m 1620:m 1616:R 1612:) 1610:m 1606:R 1604:( 1578:p 1573:G 1567:p 1555:k 1544:M 1536:M 1532:M 1508:P 1499:, 1493:Y 1484:, 1482:X 1480:/ 1478:Y 1471:P 1460:G 1458:/ 1456:F 1445:P 1443:( 1441:G 1437:P 1435:( 1433:F 1426:V 1422:G 1418:F 1414:V 1410:P 1406:R 1402:V 1398:P 1394:V 1387:K 1379:K 1361:Q 1342:R 1338:x 1334:x 1330:K 1326:x 1322:R 1318:K 1263:f 1258:f 1248:f 1243:g 1239:f 1235:g 1231:f 1223:g 1219:) 1217:x 1215:( 1213:f 1209:x 1207:( 1205:g 1200:f 1194:f 1187:f 1182:f 1136:q 1132:p 1128:q 1124:p 1109:Z 1100:) 1083:Z 1072:. 1060:p 1040:) 1037:p 1034:( 1013:Z 989:x 983:1 963:x 943:K 923:] 920:x 917:[ 914:K 893:) 889:( 858:. 856:P 852:R 848:s 844:P 840:a 836:s 834:/ 832:a 828:P 824:P 820:R 812:R 808:P 801:R 771:n 766:F 754:X 750:F 746:F 742:X 731:F 727:X 723:F 716:n 712:F 674:j 670:b 664:i 660:a 654:n 651:= 648:j 645:+ 642:i 634:= 629:n 625:c 602:i 598:x 592:i 588:c 577:0 574:= 571:i 563:= 560:) 555:i 551:x 545:i 541:b 530:0 527:= 524:i 516:( 513:) 508:i 504:x 498:i 494:a 483:0 480:= 477:i 469:( 447:i 443:x 437:i 433:a 422:0 419:= 416:i 391:] 388:] 385:x 382:[ 379:[ 375:C 345:. 343:p 337:n 332:p 317:Z 311:n 307:p 302:/ 297:Z 239:2 236:I 232:1 229:I 225:R 216:2 213:I 209:1 206:I 194:R 178:x 172:x 168:R 164:x 157:R 146:R 142:. 132:R 121:R 20:)

Index

Krull intersection theorem
mathematics
ring theory
rings
algebraic varieties
manifolds
algebraic number fields
place
commutative algebra
commutative
modules
localization of a ring
prime ideal
Wolfgang Krull
Zariski
ring
maximal
ideal
units
Jacobson radical
coprime
principal
commutative rings
Noetherian
integral domain
fields
skew fields
nilpotent
discrete valuation rings
principal ideal domains

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