1 33 honeycomb

133 honeycomb
(no image)
Type	Uniform tessellation
Schläfli symbol	{3,33,3}
Coxeter symbol	133
Coxeter-Dynkin diagram	Template:CDD or Template:CDD
7-face type	132
6-face types	122 131
5-face types	121 {34}
4-face type	111 {33}
Cell type	101
Face type	{3}
Cell figure	Square
Face figure	Triangular duoprism
Edge figure	Tetrahedral duoprism
Vertex figure	Trirectified 7-simplex
Coxeter group	${\tilde{E}}_7$, [[3,33,3]]
Properties	vertex-transitive, facet-transitive

In 7-dimensional geometry, 1₃₃ is a uniform honeycomb, also given by Schläfli symbol {3,3^3,3}, and is composed of 1₃₂ facets.

Construction

It is created by a Wythoff construction upon a set of 8 hyperplane mirrors in 7-dimensional space.

The facet information can be extracted from its Coxeter-Dynkin diagram.

Template:CDD

Removing a node on the end of one of the 3-length branch leaves the 1₃₂, its only facet type.

Template:CDD

The vertex figure is determined by removing the ringed node and ringing the neighboring node. This makes the trirectified 7-simplex, 0₃₃.

Template:CDD

The edge figure is determined by removing the ringed nodes of the vertex figure and ringing the neighboring node. This makes the tetrahedral duoprism, {3,3}×{3,3}.

Template:CDD

Kissing number

Each vertex of this polytope corresponds to the center of a 6-sphere in a moderately dense sphere packing, in which each sphere is tangent to 70 others; the best known for 7 dimensions (the kissing number) is 126.

Geometric folding

The ${\tilde{E}}_7$ group is related to the ${\tilde{F}}_4$ by a geometric folding, so this honeycomb can be projected into the 4-dimensional demitesseractic honeycomb.

${\tilde{E}}_7$	${\tilde{F}}_4$
Template:CDD	Template:CDD
{3,33,3}	{3,3,4,3}

E₇^* lattice

${\tilde{E}}_7$ contains ${\tilde{A}}_7$ as a subgroup of index 144. Both ${\tilde{E}}_7$ and ${\tilde{A}}_7$ can be seen as affine extension from $A_7$ from different nodes:

The E₇^* lattice (also called E₇²) has double the symmetry, represented by [[3,3^3,3]]. The Voronoi cell of the E₇^* lattice is the 1₃₂ polytope, and voronoi tessellation the 1₃₃ honeycomb. The E₇^* lattice is constructed by 2 copies of the E₇ lattice vertices, one from each long branch of the Coxeter diagram, and can be constructed as the union of four A₇^* lattices, also called A₇⁴:

Template:CDD ∪ Template:CDD = Template:CDD ∪ Template:CDD ∪ Template:CDD ∪ Template:CDD = dual of Template:CDD.

Related polytopes and honeycombs

The 1₃₃ is fourth in a dimensional series of uniform polytopes and honeycombs, expressed by Coxeter as 1_3k series. The final is a noncompact hyperbolic honeycomb, 1₃₄.

1_3k dimensional figures

Space	Finite				Euclidean	Hyperbolic
n	4	5	6	7	8	9
Coxeter group	A3A1	A5	D6	E7	${\tilde{E}}_7$=E7+	${\overline{T}}_8$=E7++
Coxeter diagram	Template:CDD	Template:CDD	Template:CDD	Template:CDD	Template:CDD	Template:CDD
Symmetry	[3−1,3,1]	[30,3,1]	[31,3,1]	[32,3,1]	[[33,3,1]]	[34,3,1]
Order	48	720	23,040	2,903,040	∞
Graph					-	-
Name	13,-1	130	131	132	133	134

Rectified 1₃₃ honeycomb

Rectified 133 honeycomb
(no image)
Type	Uniform tessellation
Schläfli symbol	{33,3,1}
Coxeter symbol	0331
Coxeter-Dynkin diagram	Template:CDD or Template:CDD
7-face type	Trirectified 7-simplex Rectified 1_32
6-face types	Birectified 6-simplex Birectified 6-cube Rectified 1_22
5-face types	Rectified 5-simplex Birectified 5-simplex Birectified 5-orthoplex
4-face type	5-cell Rectified 5-cell 24-cell
Cell type	{3,3} {3,4}
Face type	{3}
Vertex figure	{}×{3,3}×{3,3}
Coxeter group	${\tilde{E}}_7$, [[3,33,3]]
Properties	vertex-transitive, facet-transitive

The rectified 1₃₃ or 0₃₃₁, Coxeter diagram Template:CDD has facets Template:CDD and Template:CDD, and vertex figure Template:CDD.

See also

• 8-polytope
• 3₃₁ honeycomb

References

• H.S.M. Coxeter, Regular Polytopes, 3rd Edition, Dover New York, 1973
• Coxeter The Beauty of Geometry: Twelve Essays, Dover Publications, 1999, Template:ISBN (Chapter 3: Wythoff's Construction for Uniform Polytopes)
• Kaleidoscopes: Selected Writings of H.S.M. Coxeter, edited by F. Arthur Sherk, Peter McMullen, Anthony C. Thompson, Asia Ivic Weiss, Wiley-Interscience Publication, 1995, Template:ISBN [1]
  • (Paper 24) H.S.M. Coxeter, Regular and Semi-Regular Polytopes III, [Math. Zeit. 200 (1988) 3–45]
• Template:KlitzingPolytopes
• Template:KlitzingPolytopes

Template:Navbar-collapsible
Space	Family	${\tilde{A}}_{n-1}$	${\tilde{C}}_{n-1}$	${\tilde{B}}_{n-1}$	${\tilde{D}}_{n-1}$	${\tilde{G}}_2$ / ${\tilde{F}}_4$ / ${\tilde{E}}_{n-1}$
E2	Uniform tiling	0[3]	δ3	hδ3	qδ3	Hexagonal
E3	Uniform convex honeycomb	0[4]	δ4	hδ4	qδ4
E4	Uniform 4-honeycomb	0[5]	δ5	hδ5	qδ5	24-cell honeycomb
E5	Uniform 5-honeycomb	0[6]	δ6	hδ6	qδ6
E6	Uniform 6-honeycomb	0[7]	δ7	hδ7	qδ7	222
E7	Uniform 7-honeycomb	0[8]	δ8	hδ8	qδ8	133 • 331
E8	Uniform 8-honeycomb	0[9]	δ9	hδ9	qδ9	152 • 251 • 521
E9	Uniform 9-honeycomb	0[10]	δ10	hδ10	qδ10
E10	Uniform 10-honeycomb	0[11]	δ11	hδ11	qδ11
En-1	Uniform (n-1)-honeycomb	0[n]	δn	hδn	qδn	1k2 • 2k1 • k21