Knowledge (XXG)

Packing density

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of upper densities obtained by packings that are subcollections of the supply collection. If the supply collection consists of convex bodies of bounded diameter, there exists a packing whose packing density is equal to the packing constant, and this packing constant does not vary if the balls in the
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of the above respectively. If the density exists, the upper and lower densities are equal. Provided that any ball of the Euclidean space intersects only finitely many elements of the packing and that the diameters of the elements are bounded from above, the (upper, lower) density does not depend on
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One is often interested in packings restricted to use elements of a certain supply collection. For example, the supply collection may be the set of all balls of a given radius. The
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of the space filled by the figures making up the packing. In simplest terms, this is the ratio of the volume of bodies in a space to the volume of the space itself. In
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of a fixed body is also a common supply collection of interest, and it defines the translative packing constant of that body.
426:. The ball may also be replaced by dilations of some other convex body, but in general the resulting densities are not equal. 471: 187:, it is customary to define the density as the limit of densities exhibited in balls of larger and larger radii. If 585: 580: 358:{\displaystyle \eta =\lim _{t\to \infty }{\frac {\sum _{i=1}^{\infty }\mu (K_{i}\cap B_{t})}{\mu (B_{t})}}} 475: 39: 369:
Since this limit does not always exist, it is also useful to define the upper and lower densities as the
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and their interiors pairwise do not intersect, then the collection is a packing in
46:, the objective is usually to obtain a packing of the greatest possible density. 17: 520:
Groemer, H. (1986), "Some basic properties of packing and covering constants",
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states that 3-balls have the lowest packing constant of any convex solid. All
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definition of density are replaced by dilations of some other convex body.
443: 534: 460:. In this case, we call the packing constant the packing constant of 167:{\displaystyle \eta ={\frac {\sum _{i=1}^{n}\mu (K_{i})}{\mu (X)}}} 27:
Fraction of a space filled by objects packed into that space
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If the space being packed is infinite in measure, such as
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centered at the origin, then the density of a packing
252: 225: 97: 470:is concerned with the packing constant of 3-balls. 450:A particular supply collection of interest is all 357: 233: 166: 260: 515: 513: 8: 442:associated with a supply collection is the 498:List of shapes with known packing constant 533: 343: 322: 309: 293: 282: 275: 263: 251: 227: 226: 224: 138: 122: 111: 104: 96: 509: 7: 522:Discrete and Computational Geometry 415:for every element that intersects 294: 270: 38:of a packing in some space is the 25: 371:limit superior and limit inferior 349: 336: 328: 302: 267: 158: 152: 144: 131: 1: 234:{\displaystyle \mathbb {N} } 70:are measurable subsets of a 88:and its packing density is 602: 374:the choice of origin, and 472:Ulam's packing conjecture 454:of a fixed convex body 436:optimal packing density 430:Optimal packing density 359: 298: 235: 198:is the ball of radius 168: 127: 488:Atomic packing factor 360: 278: 236: 169: 107: 250: 223: 95: 399:can be replaced by 554:Weisstein, Eric W. 535:10.1007/BF02187693 355: 274: 231: 179:In Euclidean space 164: 586:Discrete geometry 557:"Packing Density" 468:Kepler conjecture 452:Euclidean motions 353: 259: 162: 50:In compact spaces 16:(Redirected from 593: 581:Packing problems 567: 566: 539: 538: 537: 517: 465: 459: 440:packing constant 425: 414: 398: 364: 362: 361: 356: 354: 352: 348: 347: 331: 327: 326: 314: 313: 297: 292: 276: 273: 242: 240: 238: 237: 232: 230: 203: 197: 173: 171: 170: 165: 163: 161: 147: 143: 142: 126: 121: 105: 87: 81: 69: 44:packing problems 36:packing fraction 21: 18:Packing constant 601: 600: 596: 595: 594: 592: 591: 590: 571: 570: 552: 551: 548: 543: 542: 519: 518: 511: 506: 484: 461: 455: 432: 424: 416: 412: 400: 396: 387: 375: 339: 332: 318: 305: 277: 248: 247: 221: 220: 214: 205: 199: 196: 188: 185:Euclidean space 181: 148: 134: 106: 93: 92: 83: 77: 68: 61: 55: 52: 32:packing density 28: 23: 22: 15: 12: 11: 5: 599: 597: 589: 588: 583: 573: 572: 569: 568: 547: 546:External links 544: 541: 540: 528:(2): 183–193, 508: 507: 505: 502: 501: 500: 495: 493:Sphere packing 490: 483: 480: 431: 428: 420: 408: 392: 383: 367: 366: 351: 346: 342: 338: 335: 330: 325: 321: 317: 312: 308: 304: 301: 296: 291: 288: 285: 281: 272: 269: 266: 262: 258: 255: 229: 210: 192: 180: 177: 176: 175: 160: 157: 154: 151: 146: 141: 137: 133: 130: 125: 120: 117: 114: 110: 103: 100: 66: 59: 51: 48: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 598: 587: 584: 582: 579: 578: 576: 564: 563: 558: 555: 550: 549: 545: 536: 531: 527: 523: 516: 514: 510: 503: 499: 496: 494: 491: 489: 486: 485: 481: 479: 477: 473: 469: 464: 458: 453: 448: 445: 441: 437: 429: 427: 423: 419: 411: 407: 403: 395: 391: 386: 382: 378: 372: 344: 340: 333: 323: 319: 315: 310: 306: 299: 289: 286: 283: 279: 264: 256: 253: 246: 245: 244: 218: 213: 209: 202: 195: 191: 186: 178: 155: 149: 139: 135: 128: 123: 118: 115: 112: 108: 101: 98: 91: 90: 89: 86: 80: 76: 75:measure space 73: 65: 58: 49: 47: 45: 41: 37: 33: 19: 560: 525: 521: 476:translations 462: 456: 449: 439: 435: 433: 421: 417: 409: 405: 401: 393: 389: 384: 380: 376: 368: 216: 211: 207: 200: 193: 189: 182: 84: 78: 63: 56: 53: 35: 31: 29: 575:Categories 504:References 562:MathWorld 334:μ 316:∩ 300:μ 295:∞ 280:∑ 271:∞ 268:→ 254:η 150:μ 129:μ 109:∑ 99:η 482:See also 444:supremum 215: : 40:fraction 72:compact 466:. The 62:,..., 530:doi 438:or 261:lim 243:is 54:If 34:or 577:: 559:. 524:, 512:^ 30:A 565:. 532:: 526:1 463:K 457:K 422:t 418:B 413:) 410:i 406:K 404:( 402:μ 397:) 394:t 390:B 388:∩ 385:i 381:K 379:( 377:μ 365:. 350:) 345:t 341:B 337:( 329:) 324:t 320:B 311:i 307:K 303:( 290:1 287:= 284:i 265:t 257:= 241:] 228:N 219:∈ 217:i 212:i 208:K 206:[ 201:t 194:t 190:B 174:. 159:) 156:X 153:( 145:) 140:i 136:K 132:( 124:n 119:1 116:= 113:i 102:= 85:X 79:X 67:n 64:K 60:1 57:K 20:)

Index

Packing constant
fraction
packing problems
compact
measure space
Euclidean space
limit superior and limit inferior
supremum
Euclidean motions
Kepler conjecture
Ulam's packing conjecture
translations
Atomic packing factor
Sphere packing
List of shapes with known packing constant


doi
10.1007/BF02187693
Weisstein, Eric W.
"Packing Density"
MathWorld
Categories
Packing problems
Discrete geometry

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