D7 polytope

In 7-dimensional geometry, there are 95 uniform polytopes with D₇ symmetry; 32 are unique, and 63 are shared with the B₇ symmetry. There are two regular forms, the 7-orthoplex, and 7-demicube with 14 and 64 vertices respectively.

Orthographic projections in the D₇ Coxeter plane

7-demicube

7-orthoplex

They can be visualized as symmetric orthographic projections in Coxeter planes of the D₆ Coxeter group, and other subgroups.

Graphs

Symmetric orthographic projections of these 32 polytopes can be made in the D₇, D₆, D₅, D₄, D₃, A₅, A₃, Coxeter planes. A_k has [k+1] symmetry, D_k has [2(k-1)] symmetry. B₇ is also included although only half of its [14] symmetry exists in these polytopes.

These 32 polytopes are each shown in these 8 symmetry planes, with vertices and edges drawn, and vertices colored by the number of overlapping vertices in each projective position.

#	Coxeter plane graphs								Coxeter diagram Names
	B7 [14/2]	D7 [12]	D6 [10]	D5 [8]	D4 [6]	D3 [4]	A5 [6]	A3 [4]
1									= 7-demicube Demihepteract (Hesa)
2									= Cantic 7-cube Truncated demihepteract (Thesa)
3									= Runcic 7-cube Small rhombated demihepteract (Sirhesa)
4									= Steric 7-cube Small prismated demihepteract (Sphosa)
5									= Pentic 7-cube Small cellated demihepteract (Sochesa)
6									= Hexic 7-cube Small terated demihepteract (Suthesa)
7									= Runcicantic 7-cube Great rhombated demihepteract (Girhesa)
8									= Stericantic 7-cube Prismatotruncated demihepteract (Pothesa)
9									= Steriruncic 7-cube Prismatorhomated demihepteract (Prohesa)
10									= Penticantic 7-cube Cellitruncated demihepteract (Cothesa)
11									= Pentiruncic 7-cube Cellirhombated demihepteract (Crohesa)
12									= Pentisteric 7-cube Celliprismated demihepteract (Caphesa)
13									= Hexicantic 7-cube Teritruncated demihepteract (Tuthesa)
14									= Hexiruncic 7-cube Terirhombated demihepteract (Turhesa)
15									= Hexisteric 7-cube Teriprismated demihepteract (Tuphesa)
16									= Hexipentic 7-cube Tericellated demihepteract (Tuchesa)
17									= Steriruncicantic 7-cube Great prismated demihepteract (Gephosa)
18									= Pentiruncicantic 7-cube Celligreatorhombated demihepteract (Cagrohesa)
19									= Pentistericantic 7-cube Celliprismatotruncated demihepteract (Capthesa)
20									= Pentisteriruncic 7-cube Celliprismatorhombated demihepteract (Coprahesa)
21									= Hexiruncicantic 7-cube Terigreatorhombated demihepteract (Tugrohesa)
22									= Hexistericantic 7-cube Teriprismatotruncated demihepteract (Tupthesa)
23									= Hexisteriruncic 7-cube Teriprismatorhombated demihepteract (Tuprohesa)
24									= Hexipenticantic 7-cube Tericellitruncated demihepteract (Tucothesa)
25									= Hexipentiruncic 7-cube Tericellirhombated demihepteract (Tucrohesa)
26									= Hexipentisteric 7-cube Tericelliprismated demihepteract (Tucophesa)
27									= Pentisteriruncicantic 7-cube Great cellated demihepteract (Gochesa)
28									= Hexisteriruncicantic 7-cube Terigreatoprimated demihepteract (Tugphesa)
29									= Hexipentiruncicantic 7-cube Tericelligreatorhombated demihepteract (Tucagrohesa)
30									= Hexipentistericantic 7-cube Tericelliprismatotruncated demihepteract (Tucpathesa)
31									= Hexipentisteriruncic 7-cube Tericellprismatorhombated demihepteract (Tucprohesa)
32									= Hexipentisteriruncicantic 7-cube Great terated demihepteract (Guthesa)

References

• H.S.M. Coxeter:
  • H.S.M. Coxeter, Regular Polytopes, 3rd Edition, Dover New York, 1973
• 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, ISBN 978-0-471-01003-6 ^[1]
  • (Paper 22) H.S.M. Coxeter, Regular and Semi Regular Polytopes I, [Math. Zeit. 46 (1940) 380-407, MR 2,10]
  • (Paper 23) H.S.M. Coxeter, Regular and Semi-Regular Polytopes II, [Math. Zeit. 188 (1985) 559-591]
  • (Paper 24) H.S.M. Coxeter, Regular and Semi-Regular Polytopes III, [Math. Zeit. 200 (1988) 3-45]
• N.W. Johnson: The Theory of Uniform Polytopes and Honeycombs, Ph.D. Dissertation, University of Toronto, 1966
• Klitzing, Richard. "7D uniform polytopes (polyexa)".