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Weierstrass M-test

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964: 1240: 653: 719: 1035: 713: 473: 1391: 1321: 329: 524: 265: 1537: 550: 1476: 959:{\displaystyle \left|S_{m}(x)-S_{n}(x)\right|=\left|\sum _{k=n+1}^{m}f_{k}(x)\right|{\overset {(1)}{\leq }}\sum _{k=n+1}^{m}|f_{k}(x)|\leq \sum _{k=n+1}^{m}M_{k}<\varepsilon .} 163: 1567: 189: 215: 1235:{\displaystyle \left|S(x)-S_{n}(x)\right|=\left|\lim _{m\to \infty }S_{m}(x)-S_{n}(x)\right|=\lim _{m\to \infty }\left|S_{m}(x)-S_{n}(x)\right|\leq \varepsilon .} 1617: 1609: 1644: 1003: 375: 1692: 668: 396: 1329: 1697: 1269: 277: 59:
for determining the convergence of series of real or complex numbers. It is named after the German mathematician
481: 222: 648:{\displaystyle \forall \varepsilon >0:\exists N:\forall m>n>N:\sum _{k=n+1}^{m}M_{k}<\varepsilon .} 1487: 1422: 109: 56: 32: 356: 1574: 1608:. International Series in Pure and Applied Mathematics. Vol. 8 (Second ed.). New York, NY: 335: 40: 1586: 970: 351: 339: 36: 1570: 1546: 1573:
on the Banach space. For an example of the use of this test on a Banach space, see the article
1640: 1623: 1613: 364: 88: 168: 541: 194: 60: 44: 1667: 991: 28: 52: 1686: 1656: 1603: 1671: 1599: 1413: 48: 20: 1627: 359:. Together they say that if, in addition to the above conditions, the set 1402: 84: 1401:
A more general version of the Weierstrass M-test holds if the common
1678:(Fourth ed.). Cambridge University Press. p. 49. 94:, and that there is a sequence of non-negative numbers ( 382:, then the series converges to a continuous function. 1549: 1490: 1425: 1332: 1272: 1038: 722: 671: 553: 484: 399: 280: 225: 197: 171: 112: 1262:
of partial sums converges uniformly to the function
355:. The result is often used in combination with the 1655: 1561: 1531: 1470: 1385: 1315: 1234: 958: 708:{\displaystyle \forall x\in A:\forall m>n>N} 707: 647: 518: 467: 323: 259: 209: 183: 157: 87:of real- or complex-valued functions defined on a 468:{\displaystyle S_{n}(x)=\sum _{k=1}^{n}f_{k}(x).} 1157: 1092: 1386:{\displaystyle \sum _{k=1}^{\infty }|f_{k}(x)|} 1316:{\displaystyle \sum _{k=1}^{\infty }f_{k}(x)} 349:A series satisfying the hypothesis is called 324:{\displaystyle \sum _{n=1}^{\infty }f_{n}(x)} 8: 1556: 1550: 1513: 1491: 519:{\displaystyle \sum _{n=1}^{\infty }M_{n}} 260:{\displaystyle \sum _{n=1}^{\infty }M_{n}} 1548: 1523: 1498: 1489: 1462: 1450: 1435: 1426: 1424: 1378: 1363: 1354: 1348: 1337: 1331: 1298: 1288: 1277: 1271: 1203: 1181: 1160: 1133: 1111: 1095: 1063: 1037: 941: 931: 914: 902: 887: 878: 872: 855: 833: 813: 803: 786: 754: 732: 721: 670: 630: 620: 603: 552: 510: 500: 489: 483: 447: 437: 426: 404: 398: 306: 296: 285: 279: 251: 241: 230: 224: 196: 170: 149: 137: 122: 113: 111: 1639:. McGraw-Hill Science/Engineering/Math. 1662:. McGraw-Hill Science/Engineering/Math. 43:. It applies to series whose terms are 1532:{\displaystyle \|f_{n}(x)\|\leq M_{n}} 27:is a test for determining whether an 16:Criterion about convergence of series 7: 1610:McGraw-Hill Science/Engineering/Math 1471:{\displaystyle |f_{n}(x)|\leq M_{n}} 1266:. Hence, by definition, the series 158:{\displaystyle |f_{n}(x)|\leq M_{n}} 1658:Principles of Mathematical Analysis 390:Consider the sequence of functions 1349: 1289: 1167: 1102: 687: 672: 578: 569: 554: 501: 297: 242: 14: 969:(Inequality (1) follows from the 1326:Analogously, one can prove that 55:values, and is analogous to the 1253:, this means that the sequence 1510: 1504: 1451: 1447: 1441: 1427: 1379: 1375: 1369: 1355: 1310: 1304: 1215: 1209: 1193: 1187: 1164: 1145: 1139: 1123: 1117: 1099: 1075: 1069: 1053: 1047: 1006:, it converges to some number 903: 899: 893: 879: 845: 839: 825: 819: 766: 760: 744: 738: 459: 453: 416: 410: 318: 312: 138: 134: 128: 114: 1: 1587:Example of Weierstrass M-test 1416:, in which case the premise 103:) satisfying the conditions 1676:A Course in Modern Analysis 1714: 1635:Rudin, Walter (May 1986). 1562:{\displaystyle \|\cdot \|} 1637:Real and Complex Analysis 184:{\displaystyle n\geq 1} 1654:Rudin, Walter (1976). 1563: 1533: 1472: 1387: 1353: 1317: 1293: 1236: 960: 936: 877: 808: 709: 649: 625: 520: 505: 469: 442: 325: 301: 261: 246: 211: 210:{\displaystyle x\in A} 185: 159: 1564: 1534: 1481:is to be replaced by 1473: 1393:converges uniformly. 1388: 1333: 1323:converges uniformly. 1318: 1273: 1237: 961: 910: 851: 782: 710: 650: 599: 521: 485: 470: 422: 357:uniform limit theorem 326: 281: 262: 226: 212: 186: 160: 1547: 1488: 1423: 1330: 1270: 1036: 720: 669: 551: 482: 397: 278: 223: 195: 169: 110: 1693:Functional analysis 1605:Functional Analysis 1249:does not depend on 971:triangle inequality 352:normally convergent 72:Weierstrass M-test. 1575:FrĂ©chet derivative 1559: 1529: 1468: 1405:of the functions ( 1383: 1313: 1232: 1171: 1106: 1025: >  956: 705: 645: 516: 465: 367:and the functions 321: 257: 207: 181: 155: 25:Weierstrass M-test 1698:Convergence tests 1619:978-0-07-054236-5 1156: 1091: 849: 478:Since the series 365:topological space 271:Then the series 45:bounded functions 1705: 1679: 1663: 1661: 1650: 1631: 1568: 1566: 1565: 1560: 1538: 1536: 1535: 1530: 1528: 1527: 1503: 1502: 1477: 1475: 1474: 1469: 1467: 1466: 1454: 1440: 1439: 1430: 1392: 1390: 1389: 1384: 1382: 1368: 1367: 1358: 1352: 1347: 1322: 1320: 1319: 1314: 1303: 1302: 1292: 1287: 1261: 1241: 1239: 1238: 1233: 1222: 1218: 1208: 1207: 1186: 1185: 1170: 1152: 1148: 1138: 1137: 1116: 1115: 1105: 1082: 1078: 1068: 1067: 1017:that depends on 1016: 989: 965: 963: 962: 957: 946: 945: 935: 930: 906: 892: 891: 882: 876: 871: 850: 848: 834: 832: 828: 818: 817: 807: 802: 773: 769: 759: 758: 737: 736: 714: 712: 711: 706: 661: 654: 652: 651: 646: 635: 634: 624: 619: 542:Cauchy criterion 539: 535: 525: 523: 522: 517: 515: 514: 504: 499: 474: 472: 471: 466: 452: 451: 441: 436: 409: 408: 330: 328: 327: 322: 311: 310: 300: 295: 266: 264: 263: 258: 256: 255: 245: 240: 216: 214: 213: 208: 190: 188: 187: 182: 164: 162: 161: 156: 154: 153: 141: 127: 126: 117: 61:Karl Weierstrass 1713: 1712: 1708: 1707: 1706: 1704: 1703: 1702: 1683: 1682: 1668:Whittaker, E.T. 1666: 1653: 1647: 1634: 1620: 1598: 1595: 1583: 1545: 1544: 1519: 1494: 1486: 1485: 1458: 1431: 1421: 1420: 1410: 1399: 1359: 1328: 1327: 1294: 1268: 1267: 1259: 1254: 1199: 1177: 1176: 1172: 1129: 1107: 1090: 1086: 1059: 1043: 1039: 1034: 1033: 1007: 992:Cauchy sequence 982: 977: 937: 883: 838: 809: 781: 777: 750: 728: 727: 723: 718: 717: 667: 666: 659: 658:For the chosen 626: 549: 548: 537: 532: 527: 506: 480: 479: 443: 400: 395: 394: 388: 372: 302: 276: 275: 247: 221: 220: 193: 192: 167: 166: 145: 118: 108: 107: 102: 82: 69: 57:comparison test 29:infinite series 17: 12: 11: 5: 1711: 1709: 1701: 1700: 1695: 1685: 1684: 1681: 1680: 1664: 1651: 1645: 1632: 1618: 1594: 1591: 1590: 1589: 1582: 1579: 1558: 1555: 1552: 1541: 1540: 1526: 1522: 1518: 1515: 1512: 1509: 1506: 1501: 1497: 1493: 1479: 1478: 1465: 1461: 1457: 1453: 1449: 1446: 1443: 1438: 1434: 1429: 1408: 1398: 1397:Generalization 1395: 1381: 1377: 1374: 1371: 1366: 1362: 1357: 1351: 1346: 1343: 1340: 1336: 1312: 1309: 1306: 1301: 1297: 1291: 1286: 1283: 1280: 1276: 1257: 1243: 1242: 1231: 1228: 1225: 1221: 1217: 1214: 1211: 1206: 1202: 1198: 1195: 1192: 1189: 1184: 1180: 1175: 1169: 1166: 1163: 1159: 1155: 1151: 1147: 1144: 1141: 1136: 1132: 1128: 1125: 1122: 1119: 1114: 1110: 1104: 1101: 1098: 1094: 1089: 1085: 1081: 1077: 1074: 1071: 1066: 1062: 1058: 1055: 1052: 1049: 1046: 1042: 980: 967: 966: 955: 952: 949: 944: 940: 934: 929: 926: 923: 920: 917: 913: 909: 905: 901: 898: 895: 890: 886: 881: 875: 870: 867: 864: 861: 858: 854: 847: 844: 841: 837: 831: 827: 824: 821: 816: 812: 806: 801: 798: 795: 792: 789: 785: 780: 776: 772: 768: 765: 762: 757: 753: 749: 746: 743: 740: 735: 731: 726: 715: 704: 701: 698: 695: 692: 689: 686: 683: 680: 677: 674: 656: 655: 644: 641: 638: 633: 629: 623: 618: 615: 612: 609: 606: 602: 598: 595: 592: 589: 586: 583: 580: 577: 574: 571: 568: 565: 562: 559: 556: 540:, then by the 530: 526:converges and 513: 509: 503: 498: 495: 492: 488: 476: 475: 464: 461: 458: 455: 450: 446: 440: 435: 432: 429: 425: 421: 418: 415: 412: 407: 403: 387: 384: 370: 332: 331: 320: 317: 314: 309: 305: 299: 294: 291: 288: 284: 269: 268: 254: 250: 244: 239: 236: 233: 229: 218: 206: 203: 200: 180: 177: 174: 152: 148: 144: 140: 136: 133: 130: 125: 121: 116: 98: 78: 74:Suppose that ( 68: 65: 15: 13: 10: 9: 6: 4: 3: 2: 1710: 1699: 1696: 1694: 1691: 1690: 1688: 1677: 1673: 1669: 1665: 1660: 1659: 1652: 1648: 1646:0-07-054234-1 1642: 1638: 1633: 1629: 1625: 1621: 1615: 1611: 1607: 1606: 1601: 1600:Rudin, Walter 1597: 1596: 1592: 1588: 1585: 1584: 1580: 1578: 1576: 1572: 1553: 1524: 1520: 1516: 1507: 1499: 1495: 1484: 1483: 1482: 1463: 1459: 1455: 1444: 1436: 1432: 1419: 1418: 1417: 1415: 1411: 1404: 1396: 1394: 1372: 1364: 1360: 1344: 1341: 1338: 1334: 1324: 1307: 1299: 1295: 1284: 1281: 1278: 1274: 1265: 1260: 1252: 1248: 1229: 1226: 1223: 1219: 1212: 1204: 1200: 1196: 1190: 1182: 1178: 1173: 1161: 1153: 1149: 1142: 1134: 1130: 1126: 1120: 1112: 1108: 1096: 1087: 1083: 1079: 1072: 1064: 1060: 1056: 1050: 1044: 1040: 1032: 1031: 1030: 1029:we can write 1028: 1024: 1020: 1014: 1010: 1005: 1001: 997: 993: 987: 983: 976:The sequence 974: 972: 953: 950: 947: 942: 938: 932: 927: 924: 921: 918: 915: 911: 907: 896: 888: 884: 873: 868: 865: 862: 859: 856: 852: 842: 835: 829: 822: 814: 810: 804: 799: 796: 793: 790: 787: 783: 778: 774: 770: 763: 755: 751: 747: 741: 733: 729: 724: 716: 702: 699: 696: 693: 690: 684: 681: 678: 675: 665: 664: 663: 642: 639: 636: 631: 627: 621: 616: 613: 610: 607: 604: 600: 596: 593: 590: 587: 584: 581: 575: 572: 566: 563: 560: 557: 547: 546: 545: 543: 533: 511: 507: 496: 493: 490: 486: 462: 456: 448: 444: 438: 433: 430: 427: 423: 419: 413: 405: 401: 393: 392: 391: 385: 383: 381: 377: 373: 366: 362: 358: 354: 353: 347: 345: 341: 337: 315: 307: 303: 292: 289: 286: 282: 274: 273: 272: 252: 248: 237: 234: 231: 227: 219: 204: 201: 198: 178: 175: 172: 150: 146: 142: 131: 123: 119: 106: 105: 104: 101: 97: 93: 90: 86: 81: 77: 73: 66: 64: 63:(1815-1897). 62: 58: 54: 50: 46: 42: 38: 34: 30: 26: 22: 1675: 1672:Watson, G.N. 1657: 1636: 1604: 1542: 1480: 1414:Banach space 1406: 1400: 1325: 1263: 1255: 1250: 1246: 1244: 1026: 1022: 1018: 1012: 1008: 1004:completeness 999: 995: 985: 978: 975: 968: 657: 528: 477: 389: 379: 368: 360: 350: 348: 343: 333: 270: 99: 95: 91: 79: 75: 71: 70: 24: 18: 21:mathematics 1687:Categories 1593:References 990:is thus a 536:for every 376:continuous 336:absolutely 334:converges 267:converges. 41:absolutely 35:converges 1557:‖ 1554:⋅ 1551:‖ 1517:≤ 1514:‖ 1492:‖ 1456:≤ 1350:∞ 1335:∑ 1290:∞ 1275:∑ 1227:ε 1224:≤ 1197:− 1168:∞ 1165:→ 1127:− 1103:∞ 1100:→ 1057:− 1002:, and by 951:ε 912:∑ 908:≤ 853:∑ 836:≤ 784:∑ 748:− 688:∀ 679:∈ 673:∀ 640:ε 601:∑ 579:∀ 570:∃ 558:ε 555:∀ 534:≥ 0 502:∞ 487:∑ 424:∑ 340:uniformly 298:∞ 283:∑ 243:∞ 228:∑ 202:∈ 176:≥ 143:≤ 67:Statement 37:uniformly 33:functions 1674:(1927). 1628:21163277 1602:(1991). 1581:See also 1403:codomain 191:and all 165:for all 85:sequence 1569:is the 1412:) is a 83:) is a 53:complex 1643:  1626:  1616:  1543:where 1245:Since 1021:. For 23:, the 386:Proof 363:is a 217:, and 47:with 1641:ISBN 1624:OCLC 1614:ISBN 1571:norm 948:< 700:> 694:> 637:< 591:> 585:> 561:> 374:are 338:and 49:real 39:and 1158:lim 1093:lim 998:or 994:in 973:.) 378:on 342:on 89:set 51:or 31:of 19:In 1689:: 1670:; 1622:. 1612:. 1577:. 662:, 544:, 346:. 1649:. 1630:. 1539:, 1525:n 1521:M 1511:) 1508:x 1505:( 1500:n 1496:f 1464:n 1460:M 1452:| 1448:) 1445:x 1442:( 1437:n 1433:f 1428:| 1409:n 1407:f 1380:| 1376:) 1373:x 1370:( 1365:k 1361:f 1356:| 1345:1 1342:= 1339:k 1311:) 1308:x 1305:( 1300:k 1296:f 1285:1 1282:= 1279:k 1264:S 1258:n 1256:S 1251:x 1247:N 1230:. 1220:| 1216:) 1213:x 1210:( 1205:n 1201:S 1194:) 1191:x 1188:( 1183:m 1179:S 1174:| 1162:m 1154:= 1150:| 1146:) 1143:x 1140:( 1135:n 1131:S 1124:) 1121:x 1118:( 1113:m 1109:S 1097:m 1088:| 1084:= 1080:| 1076:) 1073:x 1070:( 1065:n 1061:S 1054:) 1051:x 1048:( 1045:S 1041:| 1027:N 1023:n 1019:x 1015:) 1013:x 1011:( 1009:S 1000:C 996:R 988:) 986:x 984:( 981:n 979:S 954:. 943:k 939:M 933:m 928:1 925:+ 922:n 919:= 916:k 904:| 900:) 897:x 894:( 889:k 885:f 880:| 874:m 869:1 866:+ 863:n 860:= 857:k 846:) 843:1 840:( 830:| 826:) 823:x 820:( 815:k 811:f 805:m 800:1 797:+ 794:n 791:= 788:k 779:| 775:= 771:| 767:) 764:x 761:( 756:n 752:S 745:) 742:x 739:( 734:m 730:S 725:| 703:N 697:n 691:m 685:: 682:A 676:x 660:N 643:. 632:k 628:M 622:m 617:1 614:+ 611:n 608:= 605:k 597:: 594:N 588:n 582:m 576:: 573:N 567:: 564:0 538:n 531:n 529:M 512:n 508:M 497:1 494:= 491:n 463:. 460:) 457:x 454:( 449:k 445:f 439:n 434:1 431:= 428:k 420:= 417:) 414:x 411:( 406:n 402:S 380:A 371:n 369:f 361:A 344:A 319:) 316:x 313:( 308:n 304:f 293:1 290:= 287:n 253:n 249:M 238:1 235:= 232:n 205:A 199:x 179:1 173:n 151:n 147:M 139:| 135:) 132:x 129:( 124:n 120:f 115:| 100:n 96:M 92:A 80:n 76:f

Index

mathematics
infinite series
functions
uniformly
absolutely
bounded functions
real
complex
comparison test
Karl Weierstrass
sequence
set
absolutely
uniformly
normally convergent
uniform limit theorem
topological space
continuous
Cauchy criterion
triangle inequality
Cauchy sequence
completeness
codomain
Banach space
norm
Fréchet derivative
Example of Weierstrass M-test
Rudin, Walter
Functional Analysis
McGraw-Hill Science/Engineering/Math

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