16-cell honeycomb explained

bgcolor=#e7dcc3 colspan=216-cell honeycomb
bgcolor=#ffffff align=center colspan=2
Perspective projection

the first layer of adjacent 16-cell facets.

TypeRegular 4-honeycomb
Uniform 4-honeycomb
FamilyAlternated hypercube honeycomb
Schläfli symbol
Coxeter diagrams
=
=
4-face type
Cell type
Face type
Edge figurecube
Vertex figure
24-cell
Coxeter group

{\tilde{F}}4

= [3,3,4,3]
Dual
Propertiesvertex-transitive, edge-transitive, face-transitive, cell-transitive, 4-face-transitive
In four-dimensional Euclidean geometry, the 16-cell honeycomb is one of the three regular space-filling tessellations (or honeycombs), represented by Schläfli symbol, 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

Coordinates

Vertices can be placed at all integer coordinates (i,j,k,l), such that the sum of the coordinates is even.

D4 lattice

The 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 related D lattice (also called D) can be constructed by the union of two D4 lattices, and is identical to the C4 lattice:[6]

∪ = =

The kissing number for D is 23 = 8, (2n – 1 for n < 8, 240 for n = 8, and 2n(n – 1) for n > 8).[7]

The related D lattice (also called D and C) 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]

∪ ∪ ∪ = = ∪ .

The kissing number of the D lattice (and D4 lattice) is 24[9] and its Voronoi tessellation is a 24-cell honeycomb,, containing all rectified 16-cells (24-cell) Voronoi cells, or .[10]

Symmetry constructions

There are three different symmetry constructions of this tessellation. Each symmetry can be represented by different arrangements of colored 16-cell facets.

Coxeter groupSchläfli symbolCoxeter diagramVertex figure
Symmetry
Facets/verf

{\tilde{F}}4

= [3,3,4,3]

[3,4,3], order 1152
24: 16-cell

{\tilde{B}}4

= [3<sup>1,1</sup>,3,4]
= h =
[3,3,4], order 384
16+8: 16-cell

{\tilde{D}}4

= [3<sup>1,1,1,1</sup>]

= h
=
[3<sup>1,1,1</sup>], order 192
8+8+8: 16-cell
2×½

{\tilde{C}}4

= (4,3,3,4,2+)
ht0,48+4+4: 4-demicube
8: 16-cell

Related honeycombs

It is related to the regular hyperbolic 5-space 5-orthoplex honeycomb,, with 5-orthoplex facets, the regular 4-polytope 24-cell, with octahedral (3-orthoplex) cell, and cube, with (2-orthoplex) square faces.

It has a 2-dimensional analogue, , and as an alternated form (the demitesseractic honeycomb, h) it is related to the alternated cubic honeycomb.

See also

Regular and uniform honeycombs in 4-space:

References

Notes and References

  1. Web site: The Lattice F4.
  2. Web site: The Lattice D4.
  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. O. R. Musin . The problem of the twenty-five spheres . 2003 . Russ. Math. Surv. . 58 . 4 . 794–795 . 10.1070/RM2003v058n04ABEH000651. 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