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Abuse of notation

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137:(while possibly minimizing errors and confusion at the same time). However, since the concept of formal/syntactical correctness depends on both time and context, certain notations in mathematics that are flagged as abuse in one context could be formally correct in one or more other contexts. Time-dependent abuses of notation may occur when novel notations are introduced to a theory some time before the theory is first formalized; these may be formally corrected by solidifying and/or otherwise improving the theory. 25: 329:. In general, there is no problem with this if the object under reference is well understood, and avoiding such an abuse of notation might even make mathematical texts more pedantic and more difficult to read. When this abuse of notation may be confusing, one may distinguish between these structures by denoting 499:β€” even though they are technically distinct mathematical objects. Nevertheless, it could occur on some occasions that two different topologies are considered simultaneously on the same set. In which case, one must exercise care and use notation such as 1443:} is denoted . But in practice, if the remainder of the discussion is focused on the equivalence classes rather than the individual elements of the underlying set, then it is common to drop the square brackets in the discussion. 1077: 1390:
Another example of similar abuses occurs in statements such as "there are two non-Abelian groups of order 8", which more strictly stated means "there are two isomorphism classes of non-Abelian groups of order 8".
985:). Once this desired property is defined, there may be various ways to construct the structure, and the corresponding results are formally different objects, but which have exactly the same properties (i.e., 574: 401: 1233: 971: 533: 1377: 361: 244: 441: 497: 782: 307: 906: 863: 824: 1309: 1271: 164:β€” rather than a notation β€” is misused. Abuse of language is an almost synonymous expression for abuses that are non-notational by nature. For example, while the word 1159: 1133: 1107: 784:
be a function ..." This abuse of notation is widely used, as it simplifies the formulation, and the systematic use of a correct notation quickly becomes pedantic.
667: 611: 989:). As there is no way to distinguish these isomorphic objects through their properties, it is standard to consider them as equal, even if this is formally wrong. 638: 926: 747: 727: 707: 687: 1002: 283:. It is a common abuse of notation to use the same notation for the underlying set and the structured object (a phenomenon known as 89: 61: 68: 145:
of notation, which does not have the presentational benefits of the former and should be avoided (such as the misuse of
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in a way that is not entirely formally correct, but which might help simplify the exposition or suggest the correct
75: 1664: 46: 57: 1634: 366: 205:". Another common abuse of language consists in identifying two mathematical objects that are different, but 973:
Nevertheless, this abuse of notation is widely used, since it is more concise but generally not confusing.
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would mean nothing. However, these equalities can be legitimized and made rigorous in
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A similar abuse of notation occurs in sentences such as "Let us consider the function
275:, often called the underlying set, equipped with some additional structure, such as a 1497: 1493: 1400: 993: 407: 280: 272: 210: 981:
Many mathematical structures are defined through a characterizing property (often a
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The terms "abuse of language" and "abuse of notation" depend on context. Writing "
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Another example is the space of (classes of) measurable functions over a
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can be formed by partitioning the integers via the equivalence relation "
1072:{\displaystyle (E\times F)\times G=E\times (F\times G)=E\times F\times G} 122: 986: 866: 613:
be a function ...". This is an abuse of notation, as the name of the
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expression, not a function per se. The function that associates
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of its domain. More precisely correct phrasings include "Let
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One may encounter, in many textbooks, sentences such as "Let
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to distinguish between the different topological spaces.
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instead of is an abuse of notation. Formally, if a set
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functions, where the equivalence relation is equality "
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as both the underlying set, and the pair consisting of
457:). Most frequently, one considers only one topology on 217:
with the name of its underlying set, or identifying to
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is almost always an abuse of notation, but not in a
49:. Unsourced material may be challenged and removed. 1371: 1303: 1265: 1227: 1153: 1127: 1101: 1071: 965: 920: 900: 857: 818: 776: 741: 721: 701: 681: 661: 632: 605: 568: 527: 491: 435: 395: 355: 301: 262: 238: 1656: 1546:in the category of sets and partial functions. 463:, so there is usually no problem in referring 1419:by an equivalence relation ~, then for each 1083:But this is strictly speaking not true: if 976: 213:with its value, identifying a group with a 374: 363:the group of integers with addition, and 340: 295: 226: 109:Learn how and when to remove this message 396:{\displaystyle (\mathbb {Z} ,+,\cdot )} 209:. Other examples include identifying a 1657: 1394: 996:, which is often seen as associative: 16:Informal use of mathematical notation 1629: 1627: 1602: 1600: 579: 416:(the underlying set) and a topology 47:adding citations to reliable sources 18: 1228:{\displaystyle ((x,y),z)=(x,(y,z))} 966:{\displaystyle x\mapsto x^{2}+x+1.} 569:{\displaystyle (X,{\mathcal {T}}')} 443:which is characterized by a set of 250:of dimension three equipped with a 13: 554: 528:{\displaystyle (X,{\mathcal {T}})} 517: 484: 425: 14: 1681: 1624: 1597: 1372:{\displaystyle ((x,y),z)=(x,y,z)} 356:{\displaystyle (\mathbb {Z} ,+)} 239:{\displaystyle \mathbb {R} ^{3}} 23: 1581:"Common Errors in College Math" 1503: 436:{\displaystyle {\mathcal {T}},} 263:Structured mathematical objects 34:needs additional citations for 1608:"Glossary β€” Abuse of notation" 1573: 1366: 1348: 1342: 1333: 1321: 1318: 1298: 1286: 1254: 1242: 1222: 1219: 1207: 1198: 1192: 1183: 1171: 1168: 1048: 1036: 1018: 1006: 938: 771: 765: 759: 729:be a function of the variable 656: 650: 600: 594: 563: 542: 522: 506: 492:{\displaystyle {\mathcal {T}}} 390: 370: 350: 336: 325:of integers with addition and 1: 1566: 777:{\displaystyle x\mapsto f(x)} 129:occurs when an author uses a 302:{\displaystyle \mathbb {Z} } 7: 1549: 992:One example of this is the 257: 252:Cartesian coordinate system 10: 1686: 317:of integers together with 309:may denote the set of the 141:should be contrasted with 1427:, the equivalence class { 901:{\displaystyle x^{2}+x+1} 858:{\displaystyle x^{2}+x+1} 819:{\displaystyle x^{2}+x+1} 285:suppression of parameters 1670:Mathematical terminology 977:Equality vs. isomorphism 147:constants of integration 1304:{\displaystyle z=(y,z)} 1266:{\displaystyle (x,y)=x} 197:, it is common to call 1373: 1305: 1267: 1229: 1155: 1154:{\displaystyle z\in G} 1129: 1128:{\displaystyle y\in F} 1103: 1102:{\displaystyle x\in E} 1073: 967: 922: 902: 859: 820: 778: 743: 723: 703: 683: 663: 634: 607: 570: 529: 493: 437: 403:the ring of integers. 397: 357: 303: 277:mathematical operation 240: 207:canonically isomorphic 170:properly designates a 1665:Mathematical notation 1556:Mathematical notation 1383:β€”using the idea of a 1374: 1306: 1268: 1230: 1156: 1130: 1104: 1074: 968: 923: 903: 860: 821: 779: 744: 724: 704: 684: 669:denotes the value of 664: 635: 608: 571: 530: 494: 438: 398: 358: 304: 241: 201:"a representation of 158:abuse of terminology, 152:A related concept is 131:mathematical notation 1639:www.abstractmath.org 1612:www.abstractmath.org 1405:equivalence relation 1315: 1277: 1239: 1165: 1139: 1113: 1087: 1003: 932: 912: 873: 830: 791: 753: 733: 713: 693: 673: 662:{\displaystyle f(x)} 644: 621: 606:{\displaystyle f(x)} 588: 539: 503: 479: 420: 367: 333: 291: 269:mathematical objects 221: 43:improve this article 1585:math.vanderbilt.edu 1494:Lebesgue integrable 1395:Equivalence classes 1385:natural isomorphism 826:...", when in fact 58:"Abuse of notation" 1536:category theoretic 1448:modular arithmetic 1369: 1301: 1263: 1225: 1151: 1125: 1099: 1069: 983:universal property 963: 918: 898: 855: 816: 774: 739: 719: 699: 679: 659: 633:{\displaystyle f,} 630: 603: 566: 525: 489: 433: 410:consists of a set 393: 353: 299: 236: 172:group homomorphism 1542:can be seen as a 1498:almost everywhere 1401:equivalence class 1235:would imply that 994:Cartesian product 921:{\displaystyle x} 742:{\displaystyle x} 722:{\displaystyle f} 702:{\displaystyle x} 682:{\displaystyle f} 580:Function notation 475:and its topology 408:topological space 211:constant function 154:abuse of language 139:Abuse of notation 127:abuse of notation 119: 118: 111: 93: 1677: 1649: 1648: 1646: 1645: 1631: 1622: 1621: 1619: 1618: 1604: 1595: 1594: 1592: 1591: 1577: 1541: 1533: 1529: 1524:partial function 1521: 1492:, or classes of 1446:For example, in 1399:Referring to an 1378: 1376: 1375: 1370: 1310: 1308: 1307: 1302: 1272: 1270: 1269: 1264: 1234: 1232: 1231: 1226: 1160: 1158: 1157: 1152: 1134: 1132: 1131: 1126: 1108: 1106: 1105: 1100: 1078: 1076: 1075: 1070: 972: 970: 969: 964: 950: 949: 927: 925: 924: 919: 907: 905: 904: 899: 885: 884: 864: 862: 861: 856: 842: 841: 825: 823: 822: 817: 803: 802: 783: 781: 780: 775: 748: 746: 745: 740: 728: 726: 725: 720: 708: 706: 705: 700: 689:for the element 688: 686: 685: 680: 668: 666: 665: 660: 639: 637: 636: 631: 612: 610: 609: 604: 575: 573: 572: 567: 562: 558: 557: 534: 532: 531: 526: 521: 520: 498: 496: 495: 490: 488: 487: 474: 468: 462: 452: 442: 440: 439: 434: 429: 428: 415: 402: 400: 399: 394: 377: 362: 360: 359: 354: 343: 308: 306: 305: 300: 298: 287:). For example, 245: 243: 242: 237: 235: 234: 229: 215:binary operation 114: 107: 103: 100: 94: 92: 51: 27: 19: 1685: 1684: 1680: 1679: 1678: 1676: 1675: 1674: 1655: 1654: 1653: 1652: 1643: 1641: 1633: 1632: 1625: 1616: 1614: 1606: 1605: 1598: 1589: 1587: 1579: 1578: 1574: 1569: 1552: 1539: 1538:context, where 1531: 1527: 1509: 1506: 1469:if and only if 1397: 1381:category theory 1316: 1313: 1312: 1278: 1275: 1274: 1240: 1237: 1236: 1166: 1163: 1162: 1161:, the identity 1140: 1137: 1136: 1114: 1111: 1110: 1088: 1085: 1084: 1004: 1001: 1000: 979: 945: 941: 933: 930: 929: 928:can be denoted 913: 910: 909: 880: 876: 874: 871: 870: 837: 833: 831: 828: 827: 798: 794: 792: 789: 788: 754: 751: 750: 734: 731: 730: 714: 711: 710: 694: 691: 690: 674: 671: 670: 645: 642: 641: 622: 619: 618: 589: 586: 585: 582: 553: 552: 551: 540: 537: 536: 516: 515: 504: 501: 500: 483: 482: 480: 477: 476: 470: 464: 458: 448: 424: 423: 421: 418: 417: 411: 373: 368: 365: 364: 339: 334: 331: 330: 294: 292: 289: 288: 265: 260: 248:Euclidean space 230: 225: 224: 222: 219: 218: 115: 104: 98: 95: 52: 50: 40: 28: 17: 12: 11: 5: 1683: 1673: 1672: 1667: 1651: 1650: 1623: 1596: 1571: 1570: 1568: 1565: 1564: 1563: 1558: 1551: 1548: 1505: 1502: 1396: 1393: 1368: 1365: 1362: 1359: 1356: 1353: 1350: 1347: 1344: 1341: 1338: 1335: 1332: 1329: 1326: 1323: 1320: 1300: 1297: 1294: 1291: 1288: 1285: 1282: 1262: 1259: 1256: 1253: 1250: 1247: 1244: 1224: 1221: 1218: 1215: 1212: 1209: 1206: 1203: 1200: 1197: 1194: 1191: 1188: 1185: 1182: 1179: 1176: 1173: 1170: 1150: 1147: 1144: 1124: 1121: 1118: 1098: 1095: 1092: 1081: 1080: 1068: 1065: 1062: 1059: 1056: 1053: 1050: 1047: 1044: 1041: 1038: 1035: 1032: 1029: 1026: 1023: 1020: 1017: 1014: 1011: 1008: 978: 975: 962: 959: 956: 953: 948: 944: 940: 937: 917: 897: 894: 891: 888: 883: 879: 854: 851: 848: 845: 840: 836: 815: 812: 809: 806: 801: 797: 773: 770: 767: 764: 761: 758: 738: 718: 698: 678: 658: 655: 652: 649: 629: 626: 602: 599: 596: 593: 581: 578: 565: 561: 556: 550: 547: 544: 524: 519: 514: 511: 508: 486: 432: 427: 392: 389: 386: 383: 380: 376: 372: 352: 349: 346: 342: 338: 327:multiplication 297: 264: 261: 259: 256: 233: 228: 167:representation 117: 116: 31: 29: 22: 15: 9: 6: 4: 3: 2: 1682: 1671: 1668: 1666: 1663: 1662: 1660: 1640: 1636: 1630: 1628: 1613: 1609: 1603: 1601: 1586: 1582: 1576: 1572: 1562: 1559: 1557: 1554: 1553: 1547: 1545: 1537: 1525: 1520: 1516: 1512: 1501: 1499: 1495: 1491: 1490:measure space 1486: 1484: 1480: 1476: 1472: 1468: 1464: 1460: 1457: 1453: 1449: 1444: 1442: 1438: 1434: 1430: 1426: 1422: 1418: 1414: 1410: 1406: 1402: 1392: 1388: 1386: 1382: 1363: 1360: 1357: 1354: 1351: 1345: 1339: 1336: 1330: 1327: 1324: 1295: 1292: 1289: 1283: 1280: 1260: 1257: 1251: 1248: 1245: 1216: 1213: 1210: 1204: 1201: 1195: 1189: 1186: 1180: 1177: 1174: 1148: 1145: 1142: 1122: 1119: 1116: 1096: 1093: 1090: 1066: 1063: 1060: 1057: 1054: 1051: 1045: 1042: 1039: 1033: 1030: 1027: 1024: 1021: 1015: 1012: 1009: 999: 998: 997: 995: 990: 988: 984: 974: 960: 957: 954: 951: 946: 942: 935: 915: 895: 892: 889: 886: 881: 877: 868: 852: 849: 846: 843: 838: 834: 813: 810: 807: 804: 799: 795: 785: 768: 762: 756: 749:..." or "Let 736: 716: 696: 676: 653: 647: 627: 624: 616: 597: 591: 577: 559: 548: 545: 512: 509: 473: 467: 461: 456: 451: 446: 430: 414: 409: 406:Similarly, a 404: 387: 384: 381: 378: 347: 344: 328: 324: 320: 316: 312: 286: 282: 278: 274: 271:consist of a 270: 255: 253: 249: 231: 216: 212: 208: 204: 200: 196: 192: 188: 186: 180: 177: 173: 169: 168: 163: 159: 155: 150: 148: 144: 140: 136: 132: 128: 124: 113: 110: 102: 99:December 2017 91: 88: 84: 81: 77: 74: 70: 67: 63: 60: β€“  59: 55: 54:Find sources: 48: 44: 38: 37: 32:This article 30: 26: 21: 20: 1642:. 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Retrieved 1584: 1575: 1518: 1514: 1510: 1507: 1504:Subjectivity 1487: 1482: 1478: 1474: 1470: 1466: 1462: 1458: 1452:finite group 1445: 1440: 1436: 1432: 1428: 1424: 1420: 1412: 1408: 1398: 1389: 1082: 991: 980: 786: 583: 471: 465: 459: 449: 412: 405: 284: 266: 202: 198: 195:vector space 190: 184: 178: 166: 161: 157: 153: 151: 142: 138: 126: 120: 105: 96: 86: 79: 72: 65: 53: 41:Please help 36:verification 33: 1417:partitioned 123:mathematics 1659:Categories 1644:2019-11-03 1617:2019-11-03 1590:2019-11-03 1567:References 987:isomorphic 867:polynomial 69:newspapers 1311:, and so 1146:∈ 1120:∈ 1094:∈ 1064:× 1058:× 1043:× 1034:× 1022:× 1013:× 939:↦ 760:↦ 455:open sets 388:⋅ 321:, or the 135:intuition 1561:Misnomer 1550:See also 1544:morphism 1522:" for a 1513: : 1473:≡ 615:function 560:′ 319:addition 311:integers 281:topology 258:Examples 189:, where 160:where a 445:subsets 174:from a 83:scholar 1403:of an 313:, the 143:misuse 85:  78:  71:  64:  56:  1526:from 1485:βˆ’ 1. 1477:(mod 1456:order 865:is a 453:(the 315:group 279:or a 267:Many 193:is a 176:group 90:JSTOR 76:books 1450:, a 1273:and 1135:and 640:and 535:and 323:ring 246:the 162:term 62:news 1530:to 1500:". 1454:of 1415:is 1407:by 908:to 617:is 447:of 273:set 183:GL( 181:to 156:or 149:). 121:In 45:by 1661:: 1637:. 1626:^ 1610:. 1599:^ 1583:. 1517:β†’ 1465:~ 1439:~ 1435:| 1431:∈ 1423:∈ 1387:. 1109:, 961:1. 254:. 125:, 1647:. 1620:. 1593:. 1540:f 1532:B 1528:A 1519:B 1515:A 1511:f 1483:n 1479:n 1475:y 1471:x 1467:y 1463:x 1459:n 1441:x 1437:y 1433:X 1429:y 1425:X 1421:x 1413:X 1409:x 1367:) 1364:z 1361:, 1358:y 1355:, 1352:x 1349:( 1346:= 1343:) 1340:z 1337:, 1334:) 1331:y 1328:, 1325:x 1322:( 1319:( 1299:) 1296:z 1293:, 1290:y 1287:( 1284:= 1281:z 1261:x 1258:= 1255:) 1252:y 1249:, 1246:x 1243:( 1223:) 1220:) 1217:z 1214:, 1211:y 1208:( 1205:, 1202:x 1199:( 1196:= 1193:) 1190:z 1187:, 1184:) 1181:y 1178:, 1175:x 1172:( 1169:( 1149:G 1143:z 1123:F 1117:y 1097:E 1091:x 1079:. 1067:G 1061:F 1055:E 1052:= 1049:) 1046:G 1040:F 1037:( 1031:E 1028:= 1025:G 1019:) 1016:F 1010:E 1007:( 958:+ 955:x 952:+ 947:2 943:x 936:x 916:x 896:1 893:+ 890:x 887:+ 882:2 878:x 853:1 850:+ 847:x 844:+ 839:2 835:x 814:1 811:+ 808:x 805:+ 800:2 796:x 772:) 769:x 766:( 763:f 757:x 737:x 717:f 697:x 677:f 657:) 654:x 651:( 648:f 628:, 625:f 601:) 598:x 595:( 592:f 564:) 555:T 549:, 546:X 543:( 523:) 518:T 513:, 510:X 507:( 485:T 472:X 466:X 460:X 450:X 431:, 426:T 413:X 391:) 385:, 382:+ 379:, 375:Z 371:( 351:) 348:+ 345:, 341:Z 337:( 296:Z 232:3 227:R 203:G 199:V 191:V 187:) 185:V 179:G 112:) 106:( 101:) 97:( 87:Β· 80:Β· 73:Β· 66:Β· 39:.

Index


verification
improve this article
adding citations to reliable sources
"Abuse of notation"
news
newspapers
books
scholar
JSTOR
Learn how and when to remove this message
mathematics
mathematical notation
intuition
constants of integration
representation
group homomorphism
group
GL(V)
vector space
canonically isomorphic
constant function
binary operation
Euclidean space
Cartesian coordinate system
mathematical objects
set
mathematical operation
topology
integers

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