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Gonality of an algebraic curve

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354: 395: 162: 818: 74: 910: 547: 507: 388: 987: 598: 497: 977: 327: 676: 381: 138:≄ 3 it is no longer the case that the genus determines the gonality. The gonality of the generic curve of genus 744: 734: 671: 421: 315: 1017: 641: 537: 204: 900: 864: 563: 476: 248: 874: 512: 161:
are those with gonality 3, and this case gave rise to the name in general. Trigonal curves include the
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The Geometry of Syzygies. A second course in commutative algebra and algebraic geometry
949: 729: 709: 522: 681: 838: 785: 656: 471: 466: 323: 828: 714: 691: 341: 208: 195:, of M. Green and R. Lazarsfeld, predicts that the gonality of the algebraic curve 954: 759: 701: 603: 426: 405: 333: 319: 286: 108: 82: 51: 36: 928: 626: 451: 436: 413: 307: 212: 143: 127: 1006: 969: 739: 719: 646: 441: 373: 905: 879: 869: 859: 661: 481: 43: 780: 618: 28: 122:
is algebraically closed, then the gonality is 1 precisely for curves of
775: 636: 365: 289:, the notion (but not the terminology) originated in Section V of 959: 944: 290: 81:, then the gonality is the minimum value taken by the degrees of 211:
of high degree. In many cases the gonality is two more than the
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is zero, then the conjectured formula for the gonality is
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Code for constructing examples of special trigonal curves
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Geometric introduction to trigonal curves of genus five
297:Amodeo used the term "gonalitĂ " as early as 1893. 134:(this includes all curves of genus 2). For genus 42:is defined as the lowest degree of a nonconstant 1004: 403: 389: 243:), with respect to a given such embedding of 126:0. The gonality is 2 for curves of genus 1 ( 396: 382: 165:, of genus three and given by an equation 235:large with respect to the genus. Writing 306: 247:and the minimal free resolution for its 14: 1005: 819:Clifford's theorem on special divisors 377: 219:is an exact formula in terms of the 24: 988:Vector bundles on algebraic curves 911:Weber's theorem (Algebraic curves) 508:Hasse's theorem on elliptic curves 498:Counting points on elliptic curves 285:According to the 1900 ICM talk of 25: 1029: 599:Hurwitz's automorphisms theorem 318:. Vol. 229. New York, NY: 107:of the function field over its 824:Gonality of an algebraic curve 735:Differential of the first kind 111:generated by single functions 54:. In more algebraic terms, if 13: 1: 978:Birkhoff–Grothendieck theorem 677:Nagata's conjecture on curves 548:Schoof–Elkies–Atkin algorithm 422:Five points determine a conic 316:Graduate Texts in Mathematics 300: 538:Supersingular elliptic curve 295:Theory of Abelian Functions. 7: 745:Riemann's existence theorem 672:Hilbert's sixteenth problem 564:Elliptic curve cryptography 477:Fundamental pair of periods 249:homogeneous coordinate ring 217:Green–Lazarsfeld conjecture 10: 1034: 875:Moduli of algebraic curves 968: 919: 888: 852: 801: 794: 768: 700: 617: 581: 556: 490: 459: 450: 412: 642:Cayley–Bacharach theorem 569:Elliptic curve primality 251:, for the minimum index 901:Riemann–Hurwitz formula 865:Gromov–Witten invariant 725:Compact Riemann surface 513:Mazur's torsion theorem 518:Modular elliptic curve 364:on GitHub, written in 432:Rational normal curve 322:. pp. 171, 178. 199:can be calculated by 983:Stable vector bundle 844:Weil reciprocity law 834:Riemann–Roch theorem 814:Brill–Noether theory 750:Riemann–Roch theorem 667:Genus–degree formula 528:Mordell–Weil theorem 503:Division polynomials 221:graded Betti numbers 132:hyperelliptic curves 58:is defined over the 1018:Homological algebra 795:Structure of curves 687:Quartic plane curve 609:Hyperelliptic curve 589:De Franchis theorem 533:Nagell–Lutz theorem 201:homological algebra 193:gonality conjecture 802:Divisors on curves 594:Faltings's theorem 543:Schoof's algorithm 523:Modularity theorem 205:minimal resolution 1000: 999: 996: 995: 896:Hasse–Witt matrix 839:Weierstrass point 786:Smooth completion 755:TeichmĂŒller space 657:Cubic plane curve 577: 576: 491:Arithmetic theory 472:Elliptic integral 467:Elliptic function 16:(Redirected from 1025: 1013:Algebraic curves 829:Jacobian variety 799: 798: 702:Riemann surfaces 692:Real plane curve 652:Cramer's paradox 632:BĂ©zout's theorem 457: 456: 406:algebraic curves 398: 391: 384: 375: 374: 349: 231:dimensions, for 209:invertible sheaf 188:is of degree 4. 83:field extensions 21: 1033: 1032: 1028: 1027: 1026: 1024: 1023: 1022: 1003: 1002: 1001: 992: 964: 955:Delta invariant 933: 915: 884: 848: 809:Abel–Jacobi map 790: 764: 760:Torelli theorem 730:Dessin d'enfant 710:Belyi's theorem 696: 682:PlĂŒcker formula 613: 604:Hurwitz surface 573: 552: 486: 460:Analytic theory 452:Elliptic curves 446: 427:Projective line 414:Rational curves 408: 402: 371: 330: 320:Springer-Verlag 308:Eisenbud, David 303: 287:Federico Amodeo 265: 159:Trigonal curves 128:elliptic curves 52:projective line 37:algebraic curve 23: 22: 15: 12: 11: 5: 1031: 1021: 1020: 1015: 998: 997: 994: 993: 991: 990: 985: 980: 974: 972: 970:Vector bundles 966: 965: 963: 962: 957: 952: 947: 942: 937: 931: 925: 923: 917: 916: 914: 913: 908: 903: 898: 892: 890: 886: 885: 883: 882: 877: 872: 867: 862: 856: 854: 850: 849: 847: 846: 841: 836: 831: 826: 821: 816: 811: 805: 803: 796: 792: 791: 789: 788: 783: 778: 772: 770: 766: 765: 763: 762: 757: 752: 747: 742: 737: 732: 727: 722: 717: 712: 706: 704: 698: 697: 695: 694: 689: 684: 679: 674: 669: 664: 659: 654: 649: 644: 639: 634: 629: 623: 621: 615: 614: 612: 611: 606: 601: 596: 591: 585: 583: 579: 578: 575: 574: 572: 571: 566: 560: 558: 554: 553: 551: 550: 545: 540: 535: 530: 525: 520: 515: 510: 505: 500: 494: 492: 488: 487: 485: 484: 479: 474: 469: 463: 461: 454: 448: 447: 445: 444: 439: 437:Riemann sphere 434: 429: 424: 418: 416: 410: 409: 401: 400: 393: 386: 378: 369: 368: 358: 357: 351: 350: 328: 302: 299: 283: 282: 256: 213:Clifford index 203:means, from a 182: 181: 156: 155: 144:floor function 105: 104: 75:function field 73:) denotes the 9: 6: 4: 3: 2: 1030: 1019: 1016: 1014: 1011: 1010: 1008: 989: 986: 984: 981: 979: 976: 975: 973: 971: 967: 961: 958: 956: 953: 951: 948: 946: 943: 941: 938: 936: 934: 927: 926: 924: 922: 921:Singularities 918: 912: 909: 907: 904: 902: 899: 897: 894: 893: 891: 887: 881: 878: 876: 873: 871: 868: 866: 863: 861: 858: 857: 855: 851: 845: 842: 840: 837: 835: 832: 830: 827: 825: 822: 820: 817: 815: 812: 810: 807: 806: 804: 800: 797: 793: 787: 784: 782: 779: 777: 774: 773: 771: 769:Constructions 767: 761: 758: 756: 753: 751: 748: 746: 743: 741: 740:Klein quartic 738: 736: 733: 731: 728: 726: 723: 721: 720:Bolza surface 718: 716: 715:Bring's curve 713: 711: 708: 707: 705: 703: 699: 693: 690: 688: 685: 683: 680: 678: 675: 673: 670: 668: 665: 663: 660: 658: 655: 653: 650: 648: 647:Conic section 645: 643: 640: 638: 635: 633: 630: 628: 627:AF+BG theorem 625: 624: 622: 620: 616: 610: 607: 605: 602: 600: 597: 595: 592: 590: 587: 586: 584: 580: 570: 567: 565: 562: 561: 559: 555: 549: 546: 544: 541: 539: 536: 534: 531: 529: 526: 524: 521: 519: 516: 514: 511: 509: 506: 504: 501: 499: 496: 495: 493: 489: 483: 480: 478: 475: 473: 470: 468: 465: 464: 462: 458: 455: 453: 449: 443: 442:Twisted cubic 440: 438: 435: 433: 430: 428: 425: 423: 420: 419: 417: 415: 411: 407: 399: 394: 392: 387: 385: 380: 379: 376: 372: 367: 363: 360: 359: 356: 353: 352: 347: 343: 339: 335: 331: 329:0-387-22215-4 325: 321: 317: 313: 309: 305: 304: 298: 296: 292: 288: 280: 276: 272: 269: 268: 267: 263: 259: 254: 250: 246: 242: 238: 234: 230: 227:embedding in 226: 223:for a degree 222: 218: 214: 210: 206: 202: 198: 194: 189: 187: 179: 175: 171: 168: 167: 166: 164: 163:Picard curves 160: 153: 149: 148: 147: 145: 141: 137: 133: 129: 125: 121: 116: 114: 110: 102: 98: 94: 90: 87: 86: 85: 84: 80: 76: 72: 68: 64: 61: 57: 53: 49: 45: 41: 38: 34: 30: 19: 929: 906:Prym variety 880:Stable curve 870:Hodge bundle 860:ELSV formula 823: 662:Fermat curve 619:Plane curves 582:Higher genus 557:Applications 482:Modular form 370: 311: 294: 284: 278: 274: 270: 261: 257: 252: 244: 240: 236: 232: 228: 224: 216: 196: 192: 190: 185: 183: 177: 173: 169: 158: 157: 151: 139: 135: 119: 117: 112: 106: 100: 96: 92: 88: 78: 70: 66: 62: 55: 47: 44:rational map 39: 32: 26: 935:singularity 781:Polar curve 255:for which ÎČ 29:mathematics 1007:Categories 776:Dual curve 404:Topics in 346:1066.14001 301:References 130:) and for 889:Morphisms 637:Bitangent 366:Macaulay2 109:subfields 310:(2005). 33:gonality 18:Gonality 960:Tacnode 945:Crunode 338:2103875 291:Riemann 154:+ 3)/2. 142:is the 50:to the 940:Acnode 853:Moduli 344:  336:  326:  273:+ 1 − 215:. The 207:of an 184:where 35:of an 31:, the 124:genus 60:field 46:from 950:Cusp 324:ISBN 191:The 65:and 342:Zbl 293:'s 264:+ 1 146:of 118:If 77:of 27:In 1009:: 340:. 334:MR 332:. 314:. 281:). 260:, 172:= 115:. 95:)/ 932:k 930:A 397:e 390:t 383:v 348:. 279:C 277:( 275:b 271:r 262:i 258:i 253:i 245:C 241:C 239:( 237:b 233:d 229:r 225:d 197:C 186:Q 180:) 178:x 176:( 174:Q 170:y 152:g 150:( 140:g 136:g 120:K 113:f 103:) 101:f 99:( 97:K 93:C 91:( 89:K 79:C 71:C 69:( 67:K 63:K 56:C 48:C 40:C 20:)

Index

Gonality
mathematics
algebraic curve
rational map
projective line
field
function field
field extensions
subfields
genus
elliptic curves
hyperelliptic curves
floor function
Picard curves
homological algebra
minimal resolution
invertible sheaf
Clifford index
graded Betti numbers
homogeneous coordinate ring
Federico Amodeo
Riemann
Eisenbud, David
Graduate Texts in Mathematics
Springer-Verlag
ISBN
0-387-22215-4
MR
2103875
Zbl

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