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Shephard's problem

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22: 396: 240: 472: 51: 467: = 1 and 2, the answer to Shephard's problem is "yes". In 1967, however, Petty and Schneider showed that the answer is "no" for every 73: 626: 34: 391:{\displaystyle V_{k}(\pi _{k}(K))\leq V_{k}(\pi _{k}(L)){\mbox{ for all }}1\leq k<n\implies V_{n}(K)\leq V_{n}(L).} 488: 44: 38: 30: 683: 55: 678: 673: 200: 130: 95: 161: 234:-dimensional volume, Shephard's problem is to determine the truth or falsity of the implication 645: 635: 610: 561: 657: 584: 653: 580: 476: 118: 594: 667: 566: 549: 107: 87: 212: 134: 649: 115: 640: 615: 598: 599:"Zur einem Problem von Shephard ĂĽber die Projektionen konvexer Körper" 138: 15: 579:. Kobenhavns Univ. Mat. Inst., Copenhagen. pp. 234–241. 577:
Proceedings of the Colloquium on Convexity (Copenhagen, 1965)
471: â‰Ą 3. The solution of Shephard's problem requires 624:
Shephard, G. C. (1964), "Shadow systems of convex sets",
318: 243: 160:In this case, "centrally symmetric" means that the 390: 94:, is the following geometrical question asked by 145:is smaller than the volume of the projection of 43:but its sources remain unclear because it lacks 575:Petty, Clinton M. (1967). "Projection bodies". 473:Minkowski's first inequality for convex bodies 221:(not necessarily a coordinate hyperplane) and 554:Bulletin of the American Mathematical Society 8: 343: 339: 639: 614: 565: 531: 370: 348: 317: 299: 286: 261: 248: 242: 149:, then does it follow that the volume of 74:Learn how and when to remove this message 507: 500: 519: 7: 14: 550:"The Brunn-Minkowski inequality" 20: 382: 376: 360: 354: 340: 314: 311: 305: 292: 276: 273: 267: 254: 1: 627:Israel Journal of Mathematics 567:10.1090/S0273-0979-02-00941-2 422:)) is sometimes known as the 548:Gardner, Richard J. (2002). 560:(3): 355–405 (electronic). 700: 603:Mathematische Zeitschrift 153:is smaller than that of 106:are centrally symmetric 29:This article includes a 96:Geoffrey Colin Shephard 58:more precise citations. 489:Busemann–Petty problem 392: 393: 141:of the projection of 241: 176:, and similarly for 172:, is a translate of 458:brightness function 320: for all  121:such that whenever 641:10.1007/BF02759738 616:10.1007/BF01135693 479:of convex bodies. 475:and the notion of 388: 322: 92:Shephard's problem 31:list of references 684:Geometry problems 477:projection bodies 442: 430:and the function 321: 84: 83: 76: 691: 660: 643: 620: 618: 588: 571: 569: 535: 529: 523: 517: 511: 505: 446: 440: 412: 397: 395: 394: 389: 375: 374: 353: 352: 323: 319: 304: 303: 291: 290: 266: 265: 253: 252: 183: 79: 72: 68: 65: 59: 54:this article by 45:inline citations 24: 23: 16: 699: 698: 694: 693: 692: 690: 689: 688: 679:Convex analysis 674:Convex geometry 664: 663: 623: 595:Schneider, Rolf 593: 574: 547: 544: 539: 538: 530: 526: 518: 514: 506: 502: 497: 485: 451: 444: 438: 417: 410: 408: 366: 344: 295: 282: 257: 244: 239: 238: 229: 220: 198: 188: 181: 168:in the origin, 119:Euclidean space 80: 69: 63: 60: 49: 35:related reading 25: 21: 12: 11: 5: 697: 695: 687: 686: 681: 676: 666: 665: 662: 661: 634:(4): 229–236, 621: 590: 589: 572: 556:. New Series. 543: 540: 537: 536: 532:Schneider 1967 524: 512: 499: 498: 496: 493: 492: 491: 484: 481: 463:In dimensions 456:-dimensional) 447: 434: 413: 404: 399: 398: 387: 384: 381: 378: 373: 369: 365: 362: 359: 356: 351: 347: 342: 338: 335: 332: 329: 326: 316: 313: 310: 307: 302: 298: 294: 289: 285: 281: 278: 275: 272: 269: 264: 260: 256: 251: 247: 225: 216: 194: 193: â†’ Î  184: 82: 81: 39:external links 28: 26: 19: 13: 10: 9: 6: 4: 3: 2: 696: 685: 682: 680: 677: 675: 672: 671: 669: 659: 655: 651: 647: 642: 637: 633: 629: 628: 622: 617: 612: 608: 605:(in German). 604: 600: 596: 592: 591: 586: 582: 578: 573: 568: 563: 559: 555: 551: 546: 545: 541: 533: 528: 525: 521: 516: 513: 509: 508:Shephard 1964 504: 501: 494: 490: 487: 486: 482: 480: 478: 474: 470: 466: 461: 459: 455: 450: 437: 433: 429: 425: 421: 416: 407: 403: 385: 379: 371: 367: 363: 357: 349: 345: 336: 333: 330: 327: 324: 308: 300: 296: 287: 283: 279: 270: 262: 258: 249: 245: 237: 236: 235: 233: 228: 224: 219: 214: 211:-dimensional 210: 206: 202: 197: 192: 189: :  187: 179: 175: 171: 167: 163: 158: 156: 152: 148: 144: 140: 136: 132: 128: 124: 120: 117: 113: 109: 108:convex bodies 105: 101: 97: 93: 89: 78: 75: 67: 64:November 2019 57: 53: 47: 46: 40: 36: 32: 27: 18: 17: 631: 625: 606: 602: 576: 557: 553: 527: 515: 503: 468: 464: 462: 457: 453: 448: 435: 431: 427: 423: 419: 414: 405: 401: 400: 231: 226: 222: 217: 208: 204: 195: 190: 185: 177: 173: 169: 165: 159: 154: 150: 146: 142: 126: 122: 111: 103: 99: 98:in 1964: if 91: 85: 70: 61: 50:Please help 42: 116:dimensional 88:mathematics 56:introducing 668:Categories 542:References 520:Petty 1967 424:brightness 213:hyperplane 207:onto some 201:projection 162:reflection 135:hyperplane 650:0021-2172 609:: 71–82. 364:≤ 341:⟹ 328:≤ 297:π 280:≤ 259:π 131:projected 597:(1967). 483:See also 230:denotes 170:−K 658:0179686 585:0216369 133:onto a 52:improve 656:  648:  583:  452:as a ( 443:  439:  139:volume 137:, the 495:Notes 199:is a 180:. If 37:, or 646:ISSN 334:< 129:are 125:and 102:and 636:doi 611:doi 607:101 562:doi 426:of 203:of 164:of 110:in 86:In 670:: 654:MR 652:, 644:, 630:, 601:. 581:MR 558:39 552:. 460:. 157:? 90:, 41:, 33:, 638:: 632:2 619:. 613:: 587:. 570:. 564:: 534:. 522:. 510:. 469:n 465:n 454:k 449:k 445:Ď€ 441:o 436:k 432:V 428:K 420:K 418:( 415:k 411:Ď€ 409:( 406:k 402:V 386:. 383:) 380:L 377:( 372:n 368:V 361:) 358:K 355:( 350:n 346:V 337:n 331:k 325:1 315:) 312:) 309:L 306:( 301:k 293:( 288:k 284:V 277:) 274:) 271:K 268:( 263:k 255:( 250:k 246:V 232:k 227:k 223:V 218:k 215:Π 209:k 205:R 196:k 191:R 186:k 182:Ď€ 178:L 174:K 166:K 155:L 151:K 147:L 143:K 127:L 123:K 114:- 112:n 104:L 100:K 77:) 71:( 66:) 62:( 48:.

Index

list of references
related reading
external links
inline citations
improve
introducing
Learn how and when to remove this message
mathematics
Geoffrey Colin Shephard
convex bodies
dimensional
Euclidean space
projected
hyperplane
volume
reflection
projection
hyperplane
Minkowski's first inequality for convex bodies
projection bodies
Busemann–Petty problem
Shephard 1964
Petty 1967
Schneider 1967
"The Brunn-Minkowski inequality"
doi
10.1090/S0273-0979-02-00941-2
MR
0216369
Schneider, Rolf

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