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Normal convergence

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Every normal convergent series is uniformly convergent, locally uniformly convergent, and compactly uniformly convergent. This is very important, since it assures that any re-arrangement of the series, any derivatives or integrals of the series, and sums and products with other convergent series will
429: 621: 724:, i.e. convergence of the partial sum sequence in the topology induced by the uniform norm. Normal convergence implies norm-topology convergence if and only if the space of functions under consideration is 901: 1283: 1038: 828: 1217: 691: 508: 1129: 283: 219: 728:
with respect to the uniform norm. (The converse does not hold even for complete function spaces: for example, consider the harmonic series as a sequence of constant functions).
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and thus diverges. An example using continuous functions can be made by replacing these functions with bump functions of height 1/
97: 69: 1375: 1354: 54: 1346: 1222: 706: 76: 985: 775: 1186: 440: 1341: 629: 446: 83: 1077: 231: 43: 65: 183: 1181: 145: 424:{\displaystyle \sum _{n=0}^{\infty }\|f_{n}\|:=\sum _{n=0}^{\infty }\sup _{x\in S}|f_{n}(x)|<\infty .} 1336: 1061:(even in the weakest sense), local normal convergence and compact normal convergence are equivalent. 149: 141: 909: 551: 222: 511: 90: 1350: 137: 1058: 152:, it has the useful property that it is preserved when the order of summation is changed. 1288: 1134: 1369: 161: 725: 293: 17: 616:{\displaystyle f_{n}(x)={\begin{cases}1/n,&x=n,\\0,&x\neq n.\end{cases}}} 130: 32: 514:. However, they should not be confused; to illustrate this, consider 443:, i.e., uniform convergence of the series of nonnegative functions 951:
A series is said to be "normally convergent on compact subsets of
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As well, normal convergence of a series is different from
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The concept of normal convergence was first introduced by
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A series can be called "locally normally convergent on
1291: 1225: 1189: 1137: 1080: 988: 912: 842: 778: 632: 523: 449: 305: 234: 186: 1278:{\displaystyle \sum _{n=0}^{\infty }f_{\tau (n)}(x)} 1033:{\displaystyle \sum _{n=0}^{\infty }f_{n}\mid _{K}} 823:{\displaystyle \sum _{n=0}^{\infty }f_{n}\mid _{U}} 57:. Unsourced material may be challenged and removed. 1297: 1277: 1212:{\displaystyle \tau :\mathbb {N} \to \mathbb {N} } 1211: 1143: 1123: 1032: 931: 895: 822: 685: 615: 502: 423: 277: 213: 713:and width 1 centered at each natural number  368: 686:{\displaystyle \sum _{n=0}^{\infty }|f_{n}(x)|} 503:{\displaystyle \sum _{n=0}^{\infty }|f_{n}(x)|} 166:Leçons sur les théories générales de l'analyse 1124:{\displaystyle \sum _{n=0}^{\infty }f_{n}(x)} 278:{\displaystyle \sum _{n=0}^{\infty }f_{n}(x)} 8: 920: 913: 878: 864: 340: 327: 296:of the terms of the series converges, i.e., 1151:, then any re-arrangement of the sequence 705:), but the series of uniform norms is the 1290: 1251: 1241: 1230: 1224: 1205: 1204: 1197: 1196: 1188: 1136: 1106: 1096: 1085: 1079: 1024: 1014: 1004: 993: 987: 923: 911: 881: 871: 858: 847: 841: 814: 804: 794: 783: 777: 678: 663: 654: 648: 637: 631: 557: 546: 528: 522: 495: 480: 471: 465: 454: 448: 407: 392: 383: 371: 361: 350: 334: 321: 310: 304: 260: 250: 239: 233: 207: 206: 191: 185: 117:Learn how and when to remove this message 1327: 955:" or "compactly normally convergent on 833:is normally convergent, i.e. such that 214:{\displaystyle f_{n}:S\to \mathbb {C} } 1316:Modes of convergence (annotated index) 939:is the supremum over the domain  7: 1176:also converges normally to the same 55:adding citations to reliable sources 1242: 1097: 1005: 890: 859: 795: 757:such that the series of functions 649: 466: 415: 362: 322: 251: 25: 693:is uniformly convergent (for any 1071:converge to the "correct" value. 31: 1043:is normally convergent on  510:; this fact is essentially the 42:needs additional citations for 1272: 1266: 1261: 1255: 1201: 1118: 1112: 1021: 959:" if for every compact subset 932:{\displaystyle \|\cdot \|_{U}} 811: 679: 675: 669: 655: 540: 534: 496: 492: 486: 472: 408: 404: 398: 384: 272: 266: 203: 1: 441:uniform absolute convergence 1342:Encyclopedia of Mathematics 1335:Solomentsev, E.D. (2001) , 439:Normal convergence implies 1397: 1285:is normally convergent to 1131:is normally convergent to 967:, the series of functions 947:Compact normal convergence 1381:Convergence (mathematics) 766:restricted to the domain 722:norm-topology convergence 737:Local normal convergence 1299: 1279: 1246: 1213: 1145: 1125: 1101: 1034: 1009: 933: 897: 863: 824: 799: 687: 653: 617: 504: 470: 425: 366: 326: 279: 255: 215: 1376:Mathematical analysis 1300: 1280: 1226: 1214: 1180:. That is, for every 1146: 1126: 1081: 1035: 989: 934: 898: 843: 825: 779: 688: 633: 618: 505: 450: 426: 346: 306: 280: 235: 216: 1337:"Normal convergence" 1289: 1223: 1187: 1135: 1078: 986: 910: 840: 776: 630: 521: 447: 303: 232: 184: 164:in 1908 in his book 150:absolute-convergence 66:"Normal convergence" 51:improve this article 753:has a neighborhood 290:normally convergent 223:normed vector space 18:Normally convergent 1295: 1275: 1209: 1141: 1121: 1030: 929: 893: 820: 683: 613: 608: 512:Weierstrass M-test 500: 421: 382: 275: 211: 134:normal convergence 1298:{\displaystyle f} 1144:{\displaystyle f} 367: 292:if the series of 127: 126: 119: 101: 16:(Redirected from 1388: 1360: 1359: 1332: 1304: 1302: 1301: 1296: 1284: 1282: 1281: 1276: 1265: 1264: 1245: 1240: 1218: 1216: 1215: 1210: 1208: 1200: 1175: 1150: 1148: 1147: 1142: 1130: 1128: 1127: 1122: 1111: 1110: 1100: 1095: 1039: 1037: 1036: 1031: 1029: 1028: 1019: 1018: 1008: 1003: 938: 936: 935: 930: 928: 927: 902: 900: 899: 894: 886: 885: 876: 875: 862: 857: 829: 827: 826: 821: 819: 818: 809: 808: 798: 793: 745:" if each point 692: 690: 689: 684: 682: 668: 667: 658: 652: 647: 626:Then the series 622: 620: 619: 614: 612: 611: 561: 533: 532: 509: 507: 506: 501: 499: 485: 484: 475: 469: 464: 430: 428: 427: 422: 411: 397: 396: 387: 381: 365: 360: 339: 338: 325: 320: 284: 282: 281: 276: 265: 264: 254: 249: 220: 218: 217: 212: 210: 196: 195: 122: 115: 111: 108: 102: 100: 59: 35: 27: 21: 1396: 1395: 1391: 1390: 1389: 1387: 1386: 1385: 1366: 1365: 1364: 1363: 1357: 1334: 1333: 1329: 1324: 1312: 1287: 1286: 1247: 1221: 1220: 1185: 1184: 1173: 1166: 1159: 1152: 1133: 1132: 1102: 1076: 1075: 1067: 1059:locally compact 1020: 1010: 984: 983: 975: 949: 919: 908: 907: 906:where the norm 877: 867: 838: 837: 810: 800: 774: 773: 765: 739: 734: 732:Generalizations 707:harmonic series 659: 628: 627: 607: 606: 592: 583: 582: 568: 547: 524: 519: 518: 476: 445: 444: 437: 388: 330: 301: 300: 256: 230: 229: 187: 182: 181: 174: 158: 123: 112: 106: 103: 60: 58: 48: 36: 23: 22: 15: 12: 11: 5: 1394: 1392: 1384: 1383: 1378: 1368: 1367: 1362: 1361: 1355: 1326: 1325: 1323: 1320: 1319: 1318: 1311: 1308: 1307: 1306: 1294: 1274: 1271: 1268: 1263: 1260: 1257: 1254: 1250: 1244: 1239: 1236: 1233: 1229: 1207: 1203: 1199: 1195: 1192: 1171: 1164: 1157: 1140: 1120: 1117: 1114: 1109: 1105: 1099: 1094: 1091: 1088: 1084: 1072: 1066: 1063: 1041: 1040: 1027: 1023: 1017: 1013: 1007: 1002: 999: 996: 992: 976:restricted to 971: 948: 945: 926: 922: 918: 915: 904: 903: 892: 889: 884: 880: 874: 870: 866: 861: 856: 853: 850: 846: 831: 830: 817: 813: 807: 803: 797: 792: 789: 786: 782: 761: 738: 735: 733: 730: 681: 677: 674: 671: 666: 662: 657: 651: 646: 643: 640: 636: 624: 623: 610: 605: 602: 599: 596: 593: 591: 588: 585: 584: 581: 578: 575: 572: 569: 567: 564: 560: 556: 553: 552: 550: 545: 542: 539: 536: 531: 527: 498: 494: 491: 488: 483: 479: 474: 468: 463: 460: 457: 453: 436: 433: 432: 431: 420: 417: 414: 410: 406: 403: 400: 395: 391: 386: 380: 377: 374: 370: 364: 359: 356: 353: 349: 345: 342: 337: 333: 329: 324: 319: 316: 313: 309: 286: 285: 274: 271: 268: 263: 259: 253: 248: 245: 242: 238: 225:), the series 209: 205: 202: 199: 194: 190: 180:and functions 173: 170: 157: 154: 125: 124: 39: 37: 30: 24: 14: 13: 10: 9: 6: 4: 3: 2: 1393: 1382: 1379: 1377: 1374: 1373: 1371: 1358: 1352: 1348: 1344: 1343: 1338: 1331: 1328: 1321: 1317: 1314: 1313: 1309: 1292: 1269: 1258: 1252: 1248: 1237: 1234: 1231: 1227: 1193: 1190: 1183: 1179: 1170: 1163: 1156: 1138: 1115: 1107: 1103: 1092: 1089: 1086: 1082: 1073: 1069: 1068: 1064: 1062: 1060: 1056: 1052: 1048: 1046: 1025: 1015: 1011: 1000: 997: 994: 990: 982: 981: 980: 979: 974: 970: 966: 962: 958: 954: 946: 944: 942: 924: 916: 887: 882: 872: 868: 854: 851: 848: 844: 836: 835: 834: 815: 805: 801: 790: 787: 784: 780: 772: 771: 770: 769: 764: 760: 756: 752: 748: 744: 736: 731: 729: 727: 723: 718: 716: 712: 708: 704: 700: 696: 672: 664: 660: 644: 641: 638: 634: 603: 600: 597: 594: 589: 586: 579: 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1322:References 1065:Properties 288:is called 172:Definition 162:René Baire 77:newspapers 1347:EMS Press 1253:τ 1243:∞ 1228:∑ 1202:→ 1191:τ 1182:bijection 1098:∞ 1083:∑ 1022:∣ 1006:∞ 991:∑ 921:‖ 917:⋅ 914:‖ 891:∞ 879:‖ 865:‖ 860:∞ 845:∑ 812:∣ 796:∞ 781:∑ 650:∞ 635:∑ 598:≠ 467:∞ 452:∑ 416:∞ 376:∈ 363:∞ 348:∑ 341:‖ 328:‖ 323:∞ 308:∑ 252:∞ 237:∑ 204:→ 146:functions 1310:See also 726:complete 148:. Like 156:History 91:scholar 1353:  759:ƒ 703:ε 695:ε 142:series 93:  86:  79:  72:  64:  1053:: if 697:take 98:JSTOR 84:books 1351:ISBN 1174:...) 1051:Note 888:< 701:≥ 1/ 413:< 140:for 70:news 1074:If 1057:is 963:of 749:in 369:sup 144:of 129:In 53:by 1372:: 1349:, 1345:, 1339:, 1219:, 1167:, 1160:, 1047:. 943:. 717:. 344::= 168:. 1305:. 1293:f 1273:) 1270:x 1267:( 1262:) 1259:n 1256:( 1249:f 1238:0 1235:= 1232:n 1206:N 1198:N 1194:: 1178:ƒ 1172:3 1169:ƒ 1165:2 1162:ƒ 1158:1 1155:ƒ 1153:( 1139:f 1119:) 1116:x 1113:( 1108:n 1104:f 1093:0 1090:= 1087:n 1055:X 1045:K 1026:K 1016:n 1012:f 1001:0 998:= 995:n 978:K 973:n 969:ƒ 965:X 961:K 957:X 953:X 941:U 925:U 883:U 873:n 869:f 855:0 852:= 849:n 816:U 806:n 802:f 791:0 788:= 785:n 768:U 763:n 755:U 751:X 747:x 743:X 715:n 711:n 699:n 680:| 676:) 673:x 670:( 665:n 661:f 656:| 645:0 642:= 639:n 604:. 601:n 595:x 590:, 587:0 580:, 577:n 574:= 571:x 566:, 563:n 559:/ 555:1 549:{ 544:= 541:) 538:x 535:( 530:n 526:f 497:| 493:) 490:x 487:( 482:n 478:f 473:| 462:0 459:= 456:n 419:. 409:| 405:) 402:x 399:( 394:n 390:f 385:| 379:S 373:x 358:0 355:= 352:n 336:n 332:f 318:0 315:= 312:n 273:) 270:x 267:( 262:n 258:f 247:0 244:= 241:n 208:C 201:S 198:: 193:n 189:f 178:S 120:) 114:( 109:) 105:( 95:· 88:· 81:· 74:· 47:. 20:)

Index

Normally convergent

verification
improve this article
adding citations to reliable sources
"Normal convergence"
news
newspapers
books
scholar
JSTOR
Learn how and when to remove this message
mathematics
convergence
series
functions
absolute-convergence
René Baire
normed vector space
uniform norms
uniform absolute convergence
Weierstrass M-test
harmonic series
complete
locally compact
bijection
Modes of convergence (annotated index)
"Normal convergence"
Encyclopedia of Mathematics
EMS Press

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