Knowledge (XXG)

Apeirotope

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There are thirty regular apeirohedra in Euclidean space. These include those listed above, as well as (in the plane) polytopes of type: {∞,3}, {∞,4}, {∞,6} and in 3-dimensional space, blends of these with either an apeirogon or a line segment, and the "pure" 3-dimensional apeirohedra (12 in number)
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A skew apeirogon in two dimensions forms a zig-zag line in the plane. If the zig-zag is even and symmetrical, then the apeirogon is regular.
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Tilings of the plane and close-packed space-fillings of polyhedra are examples of honeycombs in two and three dimensions respectively.
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Skew apeirogons can be constructed in any number of dimensions. In three dimensions, a regular
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contains a least face and a greatest face, each maximal totally ordered subset (called a
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There are three regular skew apeirohedra, which look rather like polyhedral sponges:
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is strongly connected, and there are exactly two faces that lie strictly between
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are two faces whose ranks differ by two. An abstract polytope is called an
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A line divided into infinitely many finite segments is an example of an
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The regular hexagonal tiling is an example of a 3-dimensional apeirotope
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traces out a helical spiral and may be either left- or right-handed.
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Grünbaum, B. (1977). "Regular Polyhedra—Old and New".
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6 hexagons around each vertex, Coxeter symbol {6,6|3}
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4 hexagons around each vertex, Coxeter symbol {6,4|4}
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6 squares around each vertex, Coxeter symbol {4,6|4}
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There are two main geometric classes of apeirotope:
177:dimensions is an infinite example of a polytope in 392: 356:(1994), "Realizations of regular apeirotopes", 322: 298: 286: 262: 8: 118:) acts transitively on all of the flags of 310: 274: 255: 158:-dimensional manifold in a higher space 141:dimensions, which completely fill an 7: 16:Polytope with infinitely many facets 14: 107:if it has infinitely many faces. 110:An abstract polytope is called 1: 299:McMullen & Schulte (2002) 287:McMullen & Schulte (2002) 263:McMullen & Schulte (2002) 323:McMullen & Schulte (2002 181: + 1 dimensions. 114:if its automorphism group Γ( 173:In general, a honeycomb in 75:(whose elements are called 461: 445:Multi-dimensional geometry 395:Abstract Regular Polytopes 224: 203: 166: 43:which has infinitely many 227:Regular skew apeirohedron 405:10.1017/CBO9780511546686 358:Aequationes Mathematicae 342:Aeqationes mathematicae 221:Infinite skew polyhedra 24: 70:partially ordered set 22: 169:Honeycomb (geometry) 105:abstract apeirotope 87:) contains exactly 56:Abstract apeirotope 370:10.1007/BF01832961 146:-dimensional space 25: 265:, pp. 22–25. 39:is a generalized 37:infinite polytope 452: 425: 398: 380: 364:(2–3): 223–239, 349: 326: 320: 314: 308: 302: 296: 290: 284: 278: 272: 266: 260: 195:Skew apeirotopes 154:, comprising an 152:skew apeirotopes 460: 459: 455: 454: 453: 451: 450: 449: 430: 429: 428: 415: 385:McMullen, Peter 383: 354:McMullen, Peter 352: 339: 335: 330: 329: 321: 317: 311:Grünbaum (1977) 309: 305: 297: 293: 285: 281: 275:McMullen (1994) 273: 269: 261: 257: 252: 229: 223: 208: 202: 200:Skew apeirogons 197: 171: 165: 128: 58: 53: 17: 12: 11: 5: 458: 456: 448: 447: 442: 432: 431: 427: 426: 413: 381: 350: 336: 334: 331: 328: 327: 315: 303: 291: 279: 277:, p. 224. 267: 254: 253: 251: 248: 243: 242: 239: 236: 225:Main article: 222: 219: 215:skew apeirogon 206:Skew apeirogon 204:Main article: 201: 198: 196: 193: 167:Main article: 164: 161: 160: 159: 149: 127: 126:Classification 124: 57: 54: 52: 49: 15: 13: 10: 9: 6: 4: 3: 2: 457: 446: 443: 441: 438: 437: 435: 424: 420: 416: 414:0-521-81496-0 410: 406: 402: 397: 396: 390: 389:Schulte, Egon 386: 382: 379: 375: 371: 367: 363: 359: 355: 351: 347: 343: 338: 337: 332: 325:, Section 7E) 324: 319: 316: 312: 307: 304: 301:, p. 31. 300: 295: 292: 289:, p. 25. 288: 283: 280: 276: 271: 268: 264: 259: 256: 249: 247: 240: 237: 234: 233: 232: 228: 220: 218: 216: 211: 207: 199: 194: 192: 190: 185: 182: 180: 176: 170: 162: 157: 153: 150: 147: 145: 140: 136: 133: 132: 131: 125: 123: 121: 117: 113: 108: 106: 102: 98: 94: 90: 86: 82: 78: 74: 71: 67: 65: 55: 50: 48: 46: 42: 38: 34: 30: 21: 394: 361: 357: 345: 341: 333:Bibliography 318: 306: 294: 282: 270: 258: 244: 230: 212: 209: 186: 183: 178: 174: 172: 155: 143: 138: 129: 119: 115: 111: 109: 104: 100: 96: 92: 88: 84: 80: 79:) such that 76: 72: 63: 59: 36: 32: 26: 91:+ 2 faces, 434:Categories 250:References 163:Honeycombs 135:honeycombs 51:Definition 33:apeirotope 440:Polytopes 189:apeirogon 66:-polytope 62:abstract 391:(2002), 41:polytope 29:geometry 423:1965665 378:1268033 348:: 1–20. 112:regular 421:  411:  376:  45:facets 77:faces 68:is a 31:, an 409:ISBN 99:and 85:flag 401:doi 366:doi 191:. 137:in 60:An 35:or 27:In 436:: 419:MR 417:, 407:, 387:; 374:MR 372:, 362:47 360:, 346:16 344:. 122:. 47:. 403:: 368:: 313:. 179:n 175:n 156:n 148:. 144:n 139:n 120:P 116:P 101:b 97:a 93:P 89:n 81:P 73:P 64:n

Index

Regular hexagonal tiling
geometry
polytope
facets
abstract n-polytope
partially ordered set
honeycombs
n-dimensional space
skew apeirotopes
Honeycomb (geometry)
apeirogon
Skew apeirogon
skew apeirogon
Regular skew apeirohedron
McMullen & Schulte (2002)
McMullen (1994)
McMullen & Schulte (2002)
McMullen & Schulte (2002)
Grünbaum (1977)
McMullen & Schulte (2002
McMullen, Peter
doi
10.1007/BF01832961
MR
1268033
McMullen, Peter
Schulte, Egon
Abstract Regular Polytopes
doi
10.1017/CBO9780511546686

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