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Algebraic function field

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25: 320: 403: 432: 349: 718: 681:. In fact, M yields a duality (contravariant equivalence) between the category of compact connected Riemann surfaces (with non-constant 89: 61: 42: 68: 1079: 546: 645:. In fact, the function field yields a duality between the category of regular projective irreducible algebraic curves (with 75: 1125: 108: 57: 649: 721:.) In the context of this analogy, both number fields and function fields over finite fields are usually called " 1084: 46: 646: 1147: 276: 354: 451: 82: 1059: 574: 819: 573:
varieties may have the same function field!) Assigning to each variety its function field yields a
893: 741: 35: 752: 706: 447: 237: 175: 733: 570: 664: 630: 590: 156: 408: 325: 8: 566: 233: 138: 1089: 498: 434:). We see that the degree of an algebraic function field is not a well-defined notion. 248: 203: 540: 1121: 780: 772: 463: 582: 1030:
There are natural bijective correspondences between the set of valuation rings of
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sense) is especially important, since every function field of one variable over
737: 675: 638: 1141: 690: 252: 729: 722: 717:, and these counterparts are frequently easier to prove. (For example, see 714: 710: 682: 609: 122: 569:
if and only if their function fields are isomorphic. (But note that non-
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as morphisms) and the category of function fields of one variable over
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The study of function fields over a finite field has applications in
24: 1055: 577:(contravariant equivalence) between the category of varieties over 541:
Function fields arising from varieties, curves and Riemann surfaces
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Finitely generated extension field of positive transcendence degree
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as morphisms) and the category of algebraic function fields over
641:(i.e. non-singular) projective irreducible algebraic curve over 713:
have a counterpart on function fields of one variable over a
1113: 689:. A similar correspondence exists between compact connected 685:
maps as morphisms) and function fields of one variable over
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over a finite field (an important mathematical tool for
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Analogue for irreducible polynomials over a finite field
589:. (The varieties considered here are to be taken in the 629: = 1 (irreducible algebraic curves in the 411: 357: 328: 279: 637:arises as the function field of a uniquely defined 49:. Unsourced material may be challenged and removed. 700: 426: 397: 343: 314: 1117:Topics in the Theory of Algebraic Function Fields 818:Key tools to study algebraic function fields are 269:). This is a function field of one variable over 1139: 166:. Equivalently, an algebraic function field of 674:is a function field of one variable over the 1114:Gabriel Daniel & Villa Salvador (2007). 787:. These elements form a field, known as the 833:of one variable, we define the notion of a 802:) is a function field of one variable over 693:and function fields in one variable over 109:Learn how and when to remove this message 1046:, and the set of discrete valuations of 813: 736:. For example, the function field of an 751:play also an important role in solving 1140: 1080:function field of an algebraic variety 547:function field of an algebraic variety 758: 437: 315:{\displaystyle k(X)({\sqrt {X^{3}}})} 1054:. These sets can be given a natural 398:{\displaystyle k(Y)({\sqrt{Y^{2}}})} 47:adding citations to reliable sources 18: 820:absolute values, valuations, places 763:Given any algebraic function field 709:states that almost all theorems on 529:, then there are no morphisms from 442:The algebraic function fields over 13: 896:and its maximal ideal is called a 825:Given an algebraic function field 747:Function fields over the field of 744:) is an algebraic function field. 557:is an algebraic function field of 14: 1159: 791:of the algebraic function field. 597:-rational points, like the curve 892:. Each such valuation ring is a 23: 701:Number fields and finite fields 34:needs additional citations for 1107: 1085:function field (scheme theory) 943:(x) = ∞ iff 593:sense; they need not have any 421: 415: 392: 370: 367: 361: 338: 332: 309: 292: 289: 283: 1: 1100: 806:; its field of constants is 273:; it can also be written as 7: 1073: 10: 1164: 1019:) = 0 for all 497:. All these morphisms are 217: 58:"Algebraic function field" 505:is a function field over 868:, and such that for any 144:is a finitely generated 127:algebraic function field 1038:, the set of places of 894:discrete valuation ring 822:and their completions. 753:inverse Galois problems 742:public key cryptography 667:defined on a connected 567:birationally equivalent 517:is a function field in 860:and is different from 771:, we can consider the 734:error correcting codes 707:function field analogy 583:dominant rational maps 428: 399: 345: 316: 238:irreducible polynomial 222:As an example, in the 176:finite field extension 129:(often abbreviated as 1060:Zariski–Riemann space 1023: ∈  1007: ∈  939:∪{∞} such that 888: ∈  880: ∈  814:Valuations and places 665:meromorphic functions 429: 400: 346: 317: 1027: \ {0}. 565:. Two varieties are 454:from function field 427:{\displaystyle k(Y)} 409: 405:(with degree 3 over 355: 344:{\displaystyle k(X)} 326: 322:(with degree 2 over 277: 174:may be defined as a 157:transcendence degree 43:improve this article 1148:Field (mathematics) 1090:algebraic function 947: = 0, 913:discrete valuation 789:field of constants 759:Field of constants 464:ring homomorphisms 438:Category structure 424: 395: 341: 312: 249:field of fractions 204:rational functions 608:defined over the 390: 307: 236:generated by the 137:variables over a 119: 118: 111: 93: 1155: 1132: 1131: 1111: 963:) +  749:rational numbers 621: 607: 433: 431: 430: 425: 404: 402: 401: 396: 391: 389: 384: 383: 374: 350: 348: 347: 342: 321: 319: 318: 313: 308: 306: 305: 296: 260: 231: 114: 107: 103: 100: 94: 92: 51: 27: 19: 1163: 1162: 1158: 1157: 1156: 1154: 1153: 1152: 1138: 1137: 1136: 1135: 1128: 1112: 1108: 1103: 1095:Drinfeld module 1076: 1058:structure: the 979: +  816: 775:of elements of 761: 703: 676:complex numbers 669:Riemann surface 613: 612:, that is with 598: 561:variables over 543: 521:variables, and 513:variables, and 440: 410: 407: 406: 385: 379: 375: 373: 356: 353: 352: 327: 324: 323: 301: 297: 295: 278: 275: 274: 265: −  258: 243: −  229: 224:polynomial ring 220: 210:variables over 201: 192: 170:variables over 146:field extension 115: 104: 98: 95: 52: 50: 40: 28: 17: 12: 11: 5: 1161: 1151: 1150: 1134: 1133: 1126: 1105: 1104: 1102: 1099: 1098: 1097: 1092: 1087: 1082: 1075: 1072: 856:that contains 835:valuation ring 815: 812: 794:For instance, 760: 757: 738:elliptic curve 702: 699: 691:Klein surfaces 542: 539: 439: 436: 423: 420: 417: 414: 394: 388: 382: 378: 372: 369: 366: 363: 360: 340: 337: 334: 331: 311: 304: 300: 294: 291: 288: 285: 282: 219: 216: 197: 190: 131:function field 117: 116: 31: 29: 22: 15: 9: 6: 4: 3: 2: 1160: 1149: 1146: 1145: 1143: 1129: 1127:9780817645151 1123: 1119: 1118: 1110: 1106: 1096: 1093: 1091: 1088: 1086: 1083: 1081: 1078: 1077: 1071: 1069: 1065: 1061: 1057: 1053: 1049: 1045: 1041: 1037: 1033: 1028: 1026: 1022: 1018: 1014: 1010: 1006: 1002: 998: 994: 990: 986: 982: 978: 974: 970: 966: 962: 958: 954: 950: 946: 942: 938: 934: 930: 926: 922: 918: 914: 909: 907: 903: 899: 895: 891: 887: 883: 879: 875: 871: 867: 863: 859: 855: 851: 848: 844: 840: 836: 832: 828: 823: 821: 811: 809: 805: 801: 797: 792: 790: 786: 782: 778: 774: 770: 766: 756: 754: 750: 745: 743: 739: 735: 731: 726: 724: 723:global fields 720: 716: 712: 711:number fields 708: 698: 696: 692: 688: 684: 680: 677: 673: 670: 666: 662: 657: 655: 651: 648: 644: 640: 636: 632: 628: 623: 620: 616: 611: 605: 601: 596: 592: 588: 584: 580: 576: 572: 568: 564: 560: 556: 552: 549:of dimension 548: 538: 536: 532: 528: 524: 520: 516: 512: 508: 504: 500: 496: 492: 488: 484: 480: 476: 472: 469: :  468: 465: 461: 457: 453: 449: 445: 435: 418: 412: 386: 380: 376: 364: 358: 335: 329: 302: 298: 286: 280: 272: 268: 264: 257: 254: 253:quotient ring 250: 247:and form the 246: 242: 239: 235: 232:consider the 228: 225: 215: 213: 209: 205: 200: 196: 189: 185: 181: 178:of the field 177: 173: 169: 165: 161: 158: 154: 150: 147: 143: 140: 136: 132: 128: 124: 113: 110: 102: 99:December 2021 91: 88: 84: 81: 77: 74: 70: 67: 63: 60: –  59: 55: 54:Find sources: 48: 44: 38: 37: 32:This article 30: 26: 21: 20: 1120:. Springer. 1116: 1109: 1067: 1063: 1051: 1047: 1043: 1039: 1035: 1031: 1029: 1024: 1020: 1016: 1012: 1008: 1004: 1000: 996: 992: 988: 984: 980: 976: 972: 968: 964: 960: 956: 952: 948: 944: 940: 936: 932: 928: 920: 916: 912: 910: 905: 901: 897: 889: 885: 881: 877: 873: 869: 865: 861: 857: 853: 849: 845:: this is a 842: 838: 834: 830: 826: 824: 817: 807: 803: 799: 795: 793: 788: 784: 776: 768: 764: 762: 746: 730:cryptography 727: 715:finite field 704: 694: 686: 678: 671: 660: 659:The field M( 658: 653: 650:regular maps 642: 634: 626: 624: 618: 614: 603: 599: 594: 586: 578: 562: 558: 554: 550: 544: 534: 530: 526: 522: 518: 514: 510: 506: 502: 494: 490: 486: 482: 478: 474: 470: 466: 459: 455: 443: 441: 270: 266: 262: 255: 244: 240: 226: 221: 211: 207: 198: 194: 187: 183: 179: 171: 167: 163: 159: 152: 148: 141: 134: 130: 126: 120: 105: 96: 86: 79: 72: 65: 53: 41:Please help 36:verification 33: 1056:topological 999:)) for all 683:holomorphic 123:mathematics 1101:References 925:surjective 779:which are 571:isomorphic 155:which has 69:newspapers 927:function 781:algebraic 625:The case 499:injective 452:morphisms 1142:Category 1074:See also 1003:,  983:) ≥ min( 931: : 876:we have 647:dominant 489:for all 462:are the 448:category 351:) or as 847:subring 639:regular 606:+ 1 = 0 575:duality 446:form a 259:  251:of the 230:  218:Example 83:scholar 1124:  1011:, and 971:) and 631:scheme 591:scheme 581:(with 450:; the 85:  78:  71:  64:  56:  923:is a 898:place 783:over 767:over 663:) of 610:reals 553:over 525:> 501:. If 477:with 234:ideal 202:) of 193:,..., 162:over 139:field 133:) of 125:, an 90:JSTOR 76:books 1122:ISBN 955:) = 864:and 732:and 705:The 545:The 485:) = 62:news 1062:of 915:of 900:of 884:or 872:in 852:of 837:of 773:set 725:". 622:.) 533:to 509:of 493:in 458:to 206:in 121:In 45:by 1144:: 1070:. 991:), 953:xy 935:→ 911:A 908:. 810:. 755:. 697:. 656:. 617:= 602:+ 537:. 473:→ 261:/( 214:. 182:= 1130:. 1068:k 1066:/ 1064:K 1052:k 1050:/ 1048:K 1044:k 1042:/ 1040:K 1036:k 1034:/ 1032:K 1025:k 1021:a 1017:a 1015:( 1013:v 1009:K 1005:y 1001:x 997:y 995:( 993:v 989:x 987:( 985:v 981:y 977:x 975:( 973:v 969:y 967:( 965:v 961:x 959:( 957:v 951:( 949:v 945:x 941:v 937:Z 933:K 929:v 921:k 919:/ 917:K 906:k 904:/ 902:K 890:O 886:x 882:O 878:x 874:K 870:x 866:K 862:k 858:k 854:K 850:O 843:k 841:/ 839:K 831:k 829:/ 827:K 808:C 804:R 800:x 798:( 796:C 785:k 777:K 769:k 765:K 695:R 687:C 679:C 672:X 661:X 654:k 643:k 635:k 627:n 619:R 615:k 604:Y 600:X 595:k 587:k 579:k 563:k 559:n 555:k 551:n 535:L 531:K 527:m 523:n 519:m 515:L 511:n 507:k 503:K 495:k 491:a 487:a 483:a 481:( 479:f 475:L 471:K 467:f 460:L 456:K 444:k 422:) 419:Y 416:( 413:k 393:) 387:3 381:2 377:Y 371:( 368:) 365:Y 362:( 359:k 339:) 336:X 333:( 330:k 310:) 303:3 299:X 293:( 290:) 287:X 284:( 281:k 271:k 267:X 263:Y 256:k 245:X 241:Y 227:k 212:k 208:n 199:n 195:x 191:1 188:x 186:( 184:k 180:K 172:k 168:n 164:k 160:n 153:k 151:/ 149:K 142:k 135:n 112:) 106:( 101:) 97:( 87:· 80:· 73:· 66:· 39:.

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"Algebraic function field"
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mathematics
field
field extension
transcendence degree
finite field extension
rational functions
polynomial ring
ideal
irreducible polynomial
field of fractions
quotient ring
category
morphisms
ring homomorphisms
injective
function field of an algebraic variety
birationally equivalent
isomorphic
duality

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