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CM-field

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of all CM fields is similar to a CM field except that it has infinite degree. It is a quadratic extension of the union of all totally real fields
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is an order in a CM-field. Conversely any CM field arises like this from some simple complex abelian variety, unique up to isogeny.
928: 450: 923: 712:) has a center generated by an element of order 2 (complex conjugation) and the quotient by its center is the group Gal( 376: 389: 933: 862:, Publications of the Mathematical Society of Japan, vol. 11, Princeton, N.J.: Princeton University Press 516: 401: 871:, Publications of the Mathematical Society of Japan, vol. 6, Tokyo: The Mathematical Society of Japan, 93: 765: 43: 671: 218: 762:
One example of a totally imaginary field which is not CM is the number field defined by the polynomial
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is a CM-field if and only if it has a "units defect", i.e. if it contains a proper subfield
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Remak, Robert (1954), "Über algebraische Zahlkörper mit schwachem Einheitsdefekt",
39: 653:{\displaystyle \zeta _{n}^{2}+\zeta _{n}^{-2}-2=(\zeta _{n}-\zeta _{n}^{-1})^{2}.} 869:
Complex multiplication of abelian varieties and its applications to number theory
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induces an automorphism on the field which is independent of its embedding into
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Introduction to the arithmetic theory of automorphic functions
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The simplest, and motivating, example of a CM-field is an
502:{\displaystyle \mathbb {Q} (\zeta _{n}+\zeta _{n}^{-1}).} 395:
One of the most important examples of a CM-field is the
326:. In the notation given, it must change the sign of β. 768: 557: 519: 453: 404: 343: 310: 288: 256: 226: 195: 154: 128: 106: 189:
by a single square root of an element, say β =
551:is obtained from it by adjoining a square root of 270:into the real number field, σ(α) < 0. 42:, so named for a close connection to the theory of 819: 652: 543: 501: 428: 351: 318: 296: 262: 234: 205: 162: 136: 114: 704:) is a subgroup of index 2. The Galois group Gal( 54: 8: 727:is a complex abelian variety of dimension 799: 786: 773: 767: 641: 628: 623: 610: 585: 580: 567: 562: 556: 532: 521: 520: 518: 484: 479: 466: 455: 454: 452: 417: 406: 405: 403: 345: 344: 342: 312: 311: 309: 290: 289: 287: 255: 228: 227: 225: 196: 194: 156: 155: 153: 130: 129: 127: 108: 107: 105: 53:The abbreviation "CM" was introduced by ( 867:Shimura, Goro; Taniyama, Yutaka (1961), 544:{\displaystyle \mathbb {Q} (\zeta _{n})} 436:, which is generated by a primitive nth 429:{\displaystyle \mathbb {Q} (\zeta _{n})} 820:{\displaystyle x^{4}+x^{3}-x^{2}-x+1} 364: 7: 173:In other words, there is a subfield 375:mentioned above. This follows from 278:One feature of a CM-field is that 250:, so that for each embedding σ of 25: 885:Introduction to Cyclotomic fields 509:The latter is the fixed field of 206:{\displaystyle {\sqrt {\alpha }}} 883:Washington, Lawrence C. (1996). 371:is the totally real subfield of 144:, but there is no embedding of 638: 603: 538: 525: 493: 459: 423: 410: 337:whose unit group has the same 246:. For this α should be chosen 1: 440:. It is a totally imaginary 352:{\displaystyle \mathbb {Z} } 319:{\displaystyle \mathbb {C} } 297:{\displaystyle \mathbb {C} } 235:{\displaystyle \mathbb {Q} } 163:{\displaystyle \mathbb {R} } 137:{\displaystyle \mathbb {R} } 115:{\displaystyle \mathbb {C} } 27:Complex multiplication field 731:, then any abelian algebra 242:has all its roots non-real 96:. I.e., every embedding of 55:Shimura & Taniyama 1961 950: 887:(2nd ed.). New York: 390:imaginary quadratic field 213:, in such a way that the 69:is a CM-field if it is a 377:Dirichlet's unit theorem 46:. Another name used is 38:is a particular type of 929:Algebraic number theory 858:Shimura, Goro (1971), 840:Compositio Mathematica 821: 654: 545: 503: 430: 353: 320: 298: 264: 236: 207: 164: 138: 116: 44:complex multiplication 822: 672:absolute Galois group 655: 546: 504: 431: 354: 321: 299: 265: 237: 219:rational number field 208: 165: 139: 122:lies entirely within 117: 80:where the base field 766: 735:of endomorphisms of 555: 517: 451: 402: 341: 308: 286: 254: 224: 193: 152: 126: 104: 924:Field (mathematics) 636: 593: 572: 511:complex conjugation 492: 442:quadratic extension 280:complex conjugation 71:quadratic extension 817: 747:. If it has rank 2 739:has rank at most 2 650: 619: 576: 558: 541: 499: 475: 446:totally real field 426: 349: 316: 294: 260: 232: 215:minimal polynomial 203: 185:is generated over 160: 134: 112: 359:-rank as that of 263:{\displaystyle F} 201: 94:totally imaginary 61:Formal definition 16:(Redirected from 941: 910: 879: 863: 854: 826: 824: 823: 818: 804: 803: 791: 790: 778: 777: 699: 689: 679: 659: 657: 656: 651: 646: 645: 635: 627: 615: 614: 592: 584: 571: 566: 550: 548: 547: 542: 537: 536: 524: 508: 506: 505: 500: 491: 483: 471: 470: 458: 435: 433: 432: 427: 422: 421: 409: 397:cyclotomic field 358: 356: 355: 350: 348: 325: 323: 322: 317: 315: 303: 301: 300: 295: 293: 269: 267: 266: 261: 248:totally negative 241: 239: 238: 233: 231: 212: 210: 209: 204: 202: 197: 169: 167: 166: 161: 159: 143: 141: 140: 135: 133: 121: 119: 118: 113: 111: 21: 949: 948: 944: 943: 942: 940: 939: 938: 934:Complex numbers 914: 913: 899: 889:Springer-Verlag 882: 866: 857: 837: 834: 795: 782: 769: 764: 763: 755:is simple then 695: 685: 675: 637: 606: 553: 552: 528: 515: 514: 462: 449: 448: 413: 400: 399: 385: 339: 338: 329:A number field 306: 305: 284: 283: 276: 252: 251: 244:complex numbers 222: 221: 191: 190: 150: 149: 124: 123: 102: 101: 65:A number field 63: 28: 23: 22: 15: 12: 11: 5: 947: 945: 937: 936: 931: 926: 916: 915: 912: 911: 897: 880: 864: 855: 833: 830: 829: 828: 816: 813: 810: 807: 802: 798: 794: 789: 785: 781: 776: 772: 760: 721: 660: 649: 644: 640: 634: 631: 626: 622: 618: 613: 609: 605: 602: 599: 596: 591: 588: 583: 579: 575: 570: 565: 561: 540: 535: 531: 527: 523: 498: 495: 490: 487: 482: 478: 474: 469: 465: 461: 457: 425: 420: 416: 412: 408: 393: 384: 381: 347: 314: 292: 275: 272: 259: 230: 217:of β over the 200: 158: 132: 110: 62: 59: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 946: 935: 932: 930: 927: 925: 922: 921: 919: 908: 904: 900: 898:0-387-94762-0 894: 890: 886: 881: 878: 874: 870: 865: 861: 856: 853: 849: 845: 842:(in German), 841: 836: 835: 831: 814: 811: 808: 805: 800: 796: 792: 787: 783: 779: 774: 770: 761: 758: 754: 750: 746: 742: 738: 734: 730: 726: 722: 719: 715: 711: 707: 703: 698: 693: 688: 683: 678: 673: 669: 665: 661: 647: 642: 632: 629: 624: 620: 616: 611: 607: 600: 597: 594: 589: 586: 581: 577: 573: 568: 563: 559: 533: 529: 512: 496: 488: 485: 480: 476: 472: 467: 463: 447: 443: 439: 438:root of unity 418: 414: 398: 394: 391: 387: 386: 382: 380: 378: 374: 370: 366: 362: 336: 332: 327: 281: 273: 271: 257: 249: 245: 220: 216: 198: 188: 184: 180: 176: 171: 147: 99: 95: 91: 87: 83: 79: 75: 72: 68: 60: 58: 56: 51: 49: 45: 41: 37: 33: 19: 884: 868: 859: 843: 839: 756: 752: 748: 744: 740: 736: 732: 728: 724: 717: 713: 709: 705: 701: 696: 691: 686: 681: 676: 667: 663: 372: 368: 367:). In fact, 360: 334: 330: 328: 277: 247: 186: 182: 178: 174: 172: 145: 97: 89: 86:totally real 81: 77: 73: 66: 64: 52: 47: 40:number field 35: 29: 694:), and Gal( 32:mathematics 918:Categories 907:0966.11047 852:0055.26805 832:References 662:The union 365:Remak 1954 274:Properties 181:such that 846:: 35–80, 806:− 793:− 630:− 621:ζ 617:− 608:ζ 595:− 587:− 578:ζ 560:ζ 530:ζ 486:− 477:ζ 464:ζ 415:ζ 199:α 383:Examples 36:CM-field 18:CM field 877:0125113 444:of the 48:J-field 905:  895:  875:  850:  670:. The 513:, and 743:over 148:into 100:into 893:ISBN 751:and 674:Gal( 88:but 34:, a 903:Zbl 848:Zbl 723:If 282:on 177:of 92:is 84:is 57:). 30:In 920:: 901:. 891:. 873:MR 844:12 720:). 379:. 170:. 50:. 909:. 827:. 815:1 812:+ 809:x 801:2 797:x 788:3 784:x 780:+ 775:4 771:x 757:F 753:V 749:n 745:Z 741:n 737:V 733:F 729:n 725:V 718:Q 716:/ 714:Q 710:Q 708:/ 706:Q 702:Q 700:/ 697:Q 692:Q 690:/ 687:Q 682:Q 680:/ 677:Q 668:Q 664:Q 648:. 643:2 639:) 633:1 625:n 612:n 604:( 601:= 598:2 590:2 582:n 574:+ 569:2 564:n 539:) 534:n 526:( 522:Q 497:. 494:) 489:1 481:n 473:+ 468:n 460:( 456:Q 424:) 419:n 411:( 407:Q 373:K 369:F 363:( 361:K 346:Z 335:F 331:K 313:C 291:C 258:F 229:Q 187:F 183:K 179:K 175:F 157:R 146:K 131:R 109:C 98:F 90:K 82:F 78:F 76:/ 74:K 67:K 20:)

Index

CM field
mathematics
number field
complex multiplication
Shimura & Taniyama 1961
quadratic extension
totally real
totally imaginary
minimal polynomial
rational number field
complex numbers
complex conjugation
Remak 1954
Dirichlet's unit theorem
imaginary quadratic field
cyclotomic field
root of unity
quadratic extension
totally real field
complex conjugation
absolute Galois group
Zbl
0055.26805
MR
0125113
Springer-Verlag
ISBN
0-387-94762-0
Zbl
0966.11047

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