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Projection body

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Proceedings of the Conference on Convexity and Combinatorial Geometry (Univ. Oklahoma, Norman, Okla., 1971). Dept. Math., Univ. Oklahoma, Norman, Oklahoma
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Koldobsky, Alexander (1998a), "Intersection bodies, positive definite distributions, and the Busemann-Petty problem",
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showed that a centrally symmetric star-shaped body is an intersection body if and only if the function 1/||
916: 854: 182: 921: 676:{\displaystyle V_{n}(K)^{n-1}V_{n}(\Pi ^{\circ }K)\geq V_{n}(T^{n})^{n-1}V_{n}(\Pi ^{\circ }T^{n}),} 421:{\displaystyle V_{n}(K)^{n-1}V_{n}(\Pi ^{\circ }K)\leq V_{n}(B^{n})^{n-1}V_{n}(\Pi ^{\circ }B^{n}),} 211: 1101: 80: 242:
of its projection body. There are two remarkable affine isoperimetric inequality for this body.
1017: 974: 934: 884: 166: 1110: 1085: 1007: 964: 926: 876: 117: 1122: 1065: 1049: 1029: 986: 946: 898: 689: 465: 434: 123: 26: 1118: 1061: 1045: 1025: 982: 942: 894: 872: 74: 17: 776: 716: 504: 249: 191: 174: 52: 805:|| is the homogeneous function of degree 1 that is 1 on the boundary of the body, and 1132: 1012: 494: 993: 784: 1037: 47: 1099:
Zhang, Gaoyong (1991), "Restricted chord projection and affine inequalities",
156: 1021: 978: 938: 239: 969: 930: 733:-dimensional simplex, and there is equality precisely for such simplices. 1114: 1090: 1073: 880: 829: 1074:"Zur einem Problem von Shephard ĂŒber die Projektionen konvexer Körper" 493:-dimensional volume, and there is equality precisely for ellipsoids. 747:
is defined similarly, as the star body such that for any vector
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Bourgain, Jean; Lindenstrauss, J. (1988), "Projection bodies",
1044:, Kobenhavns Univ. Mat. Inst., Copenhagen, pp. 234–241, 1042:
Proceedings of the Colloquium on Convexity (Copenhagen, 1965)
771:. Equivalently, the radial function of the intersection body 871:, Lecture Notes in Math., vol. 1317, Berlin, New York: 169:
showed that the projection body of a convex body is convex.
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Koldobsky, Alexander (1998b), "Intersection bodies in R⁎",
763: â€“ 1)-dimensional volume of the intersection of 151: â€“ 1)-dimensional volume of the projection of 996:(1988), "Intersection bodies and dual mixed volumes", 719: 692: 530: 507: 468: 437: 275: 252: 214: 194: 126: 83: 55: 29: 1056:
Petty, Clinton M. (1971), "Isoperimetric problems",
869:Geometric aspects of functional analysis (1986/87) 725: 705: 675: 513: 481: 450: 420: 258: 230: 200: 135: 108: 61: 38: 801:|| is a positive definite distribution, where || 181:) used projection bodies in their solution to 8: 836:=4 but are not intersection bodies for  77:is the convex body such that for any vector 806: 794: 1089: 1011: 968: 920: 783:. Intersection bodies were introduced by 718: 697: 691: 661: 651: 638: 622: 612: 599: 580: 567: 551: 535: 529: 506: 473: 467: 442: 436: 406: 396: 383: 367: 357: 344: 325: 312: 296: 280: 274: 251: 219: 213: 193: 178: 125: 94: 82: 54: 28: 809:used this to show that the unit balls l 788: 498: 243: 170: 7: 501:) proved that for all convex bodies 648: 577: 393: 322: 246:proved that for all convex bodies 216: 127: 30: 14: 908:American Journal of Mathematics 667: 644: 619: 605: 589: 573: 548: 541: 412: 389: 364: 350: 334: 318: 293: 286: 231:{\displaystyle \Pi ^{\circ }K} 1: 755:from the origin in direction 1013:10.1016/0001-8708(88)90077-1 832:are intersection bodies for 828:-dimensional space with the 109:{\displaystyle u\in S^{n-1}} 462:-dimensional unit ball and 1155: 1036:Petty, Clinton M. (1967), 779:of the radial function of 1078:Mathematische Zeitschrift 1072:Schneider, Rolf (1967). 999:Advances in Mathematics 956:Advances in Mathematics 751:the radial function of 970:10.1006/aima.1998.1718 850:Busemann–Petty problem 727: 707: 677: 515: 483: 452: 422: 260: 232: 202: 137: 110: 63: 40: 931:10.1353/ajm.1998.0030 728: 708: 706:{\displaystyle T^{n}} 678: 516: 484: 482:{\displaystyle V_{n}} 453: 451:{\displaystyle B^{n}} 423: 261: 233: 203: 138: 136:{\displaystyle \Pi K} 111: 64: 41: 39:{\displaystyle \Pi K} 875:, pp. 250–270, 767:with the hyperplane 717: 690: 528: 505: 466: 435: 273: 250: 212: 192: 124: 81: 53: 27: 1102:Geometriae Dedicata 1038:"Projection bodies" 820:, 2 <  208:a convex body, let 1115:10.1007/BF00182294 1091:10.1007/BF01135693 1060:, pp. 26–41, 881:10.1007/BFb0081746 855:Shephard's problem 824: â‰€ âˆž in 723: 703: 673: 511: 479: 448: 418: 256: 228: 198: 183:Shephard's problem 133: 106: 59: 36: 890:978-3-540-19353-1 807:Koldobsky (1998b) 795:Koldobsky (1998a) 738:intersection body 726:{\displaystyle n} 514:{\displaystyle K} 259:{\displaystyle K} 201:{\displaystyle K} 167:Hermann Minkowski 143:in the direction 62:{\displaystyle K} 1146: 1125: 1095: 1093: 1068: 1052: 1032: 1015: 989: 972: 949: 924: 901: 840: â‰„ 5. 819: 818: 732: 730: 729: 724: 712: 710: 709: 704: 702: 701: 682: 680: 679: 674: 666: 665: 656: 655: 643: 642: 633: 632: 617: 616: 604: 603: 585: 584: 572: 571: 562: 561: 540: 539: 520: 518: 517: 512: 488: 486: 485: 480: 478: 477: 457: 455: 454: 449: 447: 446: 427: 425: 424: 419: 411: 410: 401: 400: 388: 387: 378: 377: 362: 361: 349: 348: 330: 329: 317: 316: 307: 306: 285: 284: 265: 263: 262: 257: 237: 235: 234: 229: 224: 223: 207: 205: 204: 199: 142: 140: 139: 134: 118:support function 115: 113: 112: 107: 105: 104: 68: 66: 65: 60: 45: 43: 42: 37: 1154: 1153: 1149: 1148: 1147: 1145: 1144: 1143: 1139:Convex geometry 1129: 1128: 1098: 1071: 1055: 1035: 992: 952: 922:10.1.1.610.5349 904: 891: 873:Springer-Verlag 866: 863: 846: 817: 812: 811: 810: 715: 714: 693: 688: 687: 657: 647: 634: 618: 608: 595: 576: 563: 547: 531: 526: 525: 503: 502: 469: 464: 463: 438: 433: 432: 402: 392: 379: 363: 353: 340: 321: 308: 292: 276: 271: 270: 248: 247: 215: 210: 209: 190: 189: 122: 121: 90: 79: 78: 75:Euclidean space 51: 50: 25: 24: 22:projection body 18:convex geometry 12: 11: 5: 1152: 1150: 1142: 1141: 1131: 1130: 1127: 1126: 1109:(4): 213–222, 1096: 1069: 1053: 1033: 1006:(2): 232–261, 990: 950: 915:(4): 827–840, 902: 889: 862: 859: 858: 857: 852: 845: 842: 813: 777:Funk transform 722: 700: 696: 684: 683: 672: 669: 664: 660: 654: 650: 646: 641: 637: 631: 628: 625: 621: 615: 611: 607: 602: 598: 594: 591: 588: 583: 579: 575: 570: 566: 560: 557: 554: 550: 546: 543: 538: 534: 510: 476: 472: 445: 441: 429: 428: 417: 414: 409: 405: 399: 395: 391: 386: 382: 376: 373: 370: 366: 360: 356: 352: 347: 343: 339: 336: 333: 328: 324: 320: 315: 311: 305: 302: 299: 295: 291: 288: 283: 279: 255: 227: 222: 218: 197: 159:orthogonal to 132: 129: 103: 100: 97: 93: 89: 86: 73:-dimensional 58: 35: 32: 13: 10: 9: 6: 4: 3: 2: 1151: 1140: 1137: 1136: 1134: 1124: 1120: 1116: 1112: 1108: 1104: 1103: 1097: 1092: 1087: 1083: 1080:(in German). 1079: 1075: 1070: 1067: 1063: 1059: 1054: 1051: 1047: 1043: 1039: 1034: 1031: 1027: 1023: 1019: 1014: 1009: 1005: 1001: 1000: 995: 994:Lutwak, Erwin 991: 988: 984: 980: 976: 971: 966: 962: 958: 957: 951: 948: 944: 940: 936: 932: 928: 923: 918: 914: 910: 909: 903: 900: 896: 892: 886: 882: 878: 874: 870: 865: 864: 860: 856: 853: 851: 848: 847: 843: 841: 839: 835: 831: 827: 823: 816: 808: 804: 800: 796: 792: 790: 786: 782: 778: 774: 770: 766: 762: 758: 754: 750: 746: 742: 739: 734: 720: 698: 694: 670: 662: 658: 652: 639: 635: 629: 626: 623: 613: 609: 600: 596: 592: 586: 581: 568: 564: 558: 555: 552: 544: 536: 532: 524: 523: 522: 508: 500: 496: 492: 474: 470: 461: 443: 439: 415: 407: 403: 397: 384: 380: 374: 371: 368: 358: 354: 345: 341: 337: 331: 326: 313: 309: 303: 300: 297: 289: 281: 277: 269: 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919:  897:  887:  830:l norm 785:Lutwak 686:where 431:where 116:, the 20:, the 495:Zhang 46:of a 1018:ISSN 975:ISSN 935:ISSN 885:ISBN 789:1988 736:The 499:1991 188:For 179:1967 173:and 1111:doi 1086:doi 1082:101 1008:doi 965:doi 961:136 927:doi 913:120 877:doi 791:). 743:of 489:is 163:. 120:of 69:in 16:In 1135:: 1119:MR 1117:, 1107:39 1105:, 1076:. 1062:MR 1046:MR 1040:, 1026:MR 1024:, 1016:, 1004:71 1002:, 983:MR 981:, 973:, 959:, 943:MR 941:, 933:, 925:, 911:, 895:MR 893:, 883:, 773:IK 753:IK 741:IK 521:, 266:, 185:. 1113:: 1094:. 1088:: 1010:: 967:: 929:: 879:: 838:n 834:n 826:n 822:p 815:n 803:x 799:x 781:K 769:u 765:K 761:n 757:u 749:u 745:K 721:n 699:n 695:T 671:, 668:) 663:n 659:T 645:( 640:n 636:V 630:1 624:n 620:) 614:n 610:T 606:( 601:n 597:V 590:) 587:K 574:( 569:n 565:V 559:1 553:n 549:) 545:K 542:( 537:n 533:V 509:K 491:n 475:n 471:V 460:n 444:n 440:B 416:, 413:) 408:n 404:B 390:( 385:n 381:V 375:1 369:n 365:) 359:n 355:B 351:( 346:n 342:V 335:) 332:K 319:( 314:n 310:V 304:1 298:n 294:) 290:K 287:( 282:n 278:V 254:K 226:K 196:K 161:u 153:K 149:n 145:u 131:K 102:1 96:n 92:S 85:u 71:n 57:K 34:K

Index

convex geometry
convex body
Euclidean space
support function
hyperplane
Hermann Minkowski
Petty (1967)
Schneider
1967
Shephard's problem
polar body
Petty (1971)
Zhang
1991
Funk transform
Lutwak
1988
Koldobsky (1998a)
Koldobsky (1998b)
l norm
Busemann–Petty problem
Shephard's problem
Springer-Verlag
doi
10.1007/BFb0081746
ISBN
978-3-540-19353-1
MR
0950986
American Journal of Mathematics

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