词条 | 16-cell honeycomb | ||||||||||||||||||||||||||||||||||||||||||||||||||||
释义 |
In four-dimensional Euclidean geometry, the 16-cell honeycomb is one of the three regular space-filling tessellations (or honeycombs), represented by Schläfli symbol {3,3,4,3}, and constructed by a 4-dimensional packing of 16-cell facets, three around every face. Its dual is the 24-cell honeycomb. Its vertex figure is a 24-cell. The vertex arrangement is called the B4, D4, or F4 lattice.[1][2] Alternate names
CoordinatesVertices can be placed at all integer coordinates (i,j,k,l), such that the sum of the coordinates is even. D4 latticeThe vertex arrangement of the 16-cell honeycomb is called the D4 lattice or F4 lattice.[2] The vertices of this lattice are the centers of the 3-spheres in the densest known packing of equal spheres in 4-space;[3] its kissing number is 24, which is also the same as the kissing number in R4, as proved by Oleg Musin in 2003.[4][5] The D{{sup sub|+|4}} lattice (also called D{{sup sub|2|4}}) can be constructed by the union of two D4 lattices, and is identical to the tesseractic honeycomb:[6] {{CDD|nodes_10ru|split2|node|split1|nodes}} ∪ {{CDD|nodes_01rd|split2|node|split1|nodes}} = {{CDD|node_1|4|node|3|node|split1|nodes}} = {{CDD|node_1|4|node|3|node|3|node|4|node}} This packing is only a lattice for even dimensions. The kissing number is 23 = 8, (2n – 1 for n < 8, 240 for n = 8, and 2n(n – 1) for n > 8).[7] The D{{sup sub|*|4}} lattice (also called D{{sup sub|4|4}} and C{{sup sub|2|4}}) can be constructed by the union of all four D4 lattices, but it is identical to the D4 lattice: It is also the 4-dimensional body centered cubic, the union of two 4-cube honeycombs in dual positions.[8] {{CDD|nodes_10ru|split2|node|split1|nodes}} ∪ {{CDD|nodes_01rd|split2|node|split1|nodes}} ∪ {{CDD|nodes|split2|node|split1|nodes_10lu}} ∪ {{CDD|nodes|split2|node|split1|nodes_01ld}} = {{CDD|nodes_10ru|split2|node|split1|nodes}} = {{CDD|nodes_10r|4a4b|nodes|split2|node}} ∪ {{CDD|nodes_01r|4a4b|nodes|split2|node}}. The kissing number of the D{{sup sub|*|4}} lattice (and D4 lattice) is 24[9] and its Voronoi tessellation is a 24-cell honeycomb, {{CDD|node_1|split1|nodes|4a4b|nodes}}, containing all rectified 16-cells (24-cell) Voronoi cells, {{CDD|node|4|node|3|node_1|3|node}} or {{CDD|node_1|3|node|4|node|3|node}}.[10] Symmetry constructionsThere are three different symmetry constructions of this tessellation. Each symmetry can be represented by different arrangements of colored 16-cell facets.
Related honeycombsIt is related to the regular hyperbolic 5-space 5-orthoplex honeycomb, {3,3,3,4,3}, with 5-orthoplex facets, the regular 4-polytope 24-cell, {3,4,3} with octahedral (3-orthoplex) cell, and cube {4,3}, with (2-orthoplex) square faces. It has a 2-dimensional analogue, {3,6}, and as an alternated form (the demitesseractic honeycomb, h{4,3,3,4}) it is related to the alternated cubic honeycomb. {{D5 honeycombs}}See alsoRegular and uniform honeycombs in 4-space:
Notes1. ^http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/F4.html 2. ^1 http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/D4.html 3. ^Conway and Sloane, Sphere packings, lattices, and groups, 1.4 n-dimensional packings, p.9 4. ^Conway and Sloane, Sphere packings, lattices, and groups, 1.5 Sphere packing problem summary of results. , p.12 5. ^{{cite journal |author=O. R. Musin |title=The problem of the twenty-five spheres |year=2003 |journal=Russ. Math. Surv. |volume=58 |pages=794–795 |doi=10.1070/RM2003v058n04ABEH000651|bibcode=2003RuMaS..58..794M }} 6. ^Conway and Sloane, Sphere packings, lattices, and groups, 7.3 The packing D3+, p.119 7. ^Conway and Sloane, Sphere packings, lattices, and groups, p. 119 8. ^Conway and Sloane, Sphere packings, lattices, and groups, 7.4 The dual lattice D3*, p.120 9. ^Conway and Sloane, Sphere packings, lattices, and groups, p. 120 10. ^Conway and Sloane, Sphere packings, lattices, and groups, p. 466 References
3 : Honeycombs (geometry)|5-polytopes|Regular tessellations |
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