Demihepteract (7-demicube) | ||
---|---|---|
Petrie polygon projection | ||
Type | Uniform 7-polytope | |
Family | demihypercube | |
Coxeter symbol | 141 | |
Schläfli symbol | {3,34,1} = h{4,35} s{21,1,1,1,1,1} | |
Coxeter diagrams | = | |
6-faces | 78 | 14 {31,3,1} 64 {35} |
5-faces | 532 | 84 {31,2,1} 448 {34} |
4-faces | 1624 | 280 {31,1,1} 1344 {33} |
Cells | 2800 | 560 {31,0,1} 2240 {3,3} |
Faces | 2240 | {3} |
Edges | 672 | |
Vertices | 64 | |
Vertex figure | Rectified 6-simplex | |
Symmetry group | D7, [34,1,1] = [1+,4,35] [26]+ | |
Dual | ? | |
Properties | convex |
In geometry, a demihepteract or 7-demicube is a uniform 7-polytope, constructed from the 7-hypercube (hepteract) with alternated vertices removed. It is part of a dimensionally infinite family of uniform polytopes called demihypercubes.
E. L. Elte identified it in 1912 as a semiregular polytope, labeling it as HM7 for a 7-dimensional half measure polytope.
Coxeter named this polytope as 141 from its Coxeter diagram, with a ring on one of the 1-length branches, and Schläfli symbol or {3,34,1}.
Cartesian coordinates for the vertices of a demihepteract centered at the origin are alternate halves of the hepteract:
with an odd number of plus signs.
Coxeter plane | B7 | D7 | D6 |
---|---|---|---|
Graph | |||
Dihedral symmetry | [14/2] | [12] | [10] |
Coxeter plane | D5 | D4 | D3 |
Graph | |||
Dihedral symmetry | [8] | [6] | [4] |
Coxeter plane | A5 | A3 | |
Graph | |||
Dihedral symmetry | [6] | [4] |
This configuration matrix represents the 7-demicube. The rows and columns correspond to vertices, edges, faces, cells, 4-faces, 5-faces and 6-faces. The diagonal numbers say how many of each element occur in the whole 7-demicube. The nondiagonal numbers say how many of the column's element occur in or at the row's element. [1] [2]
The diagonal f-vector numbers are derived through the Wythoff construction, dividing the full group order of a subgroup order by removing one mirror at a time. [3]
D7 | k-face | fk | f0 | f1 | f2 | f3 | f4 | f5 | f6 | k-figures | notes | |||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
A6 | ( ) | f0 | 64 | 21 | 105 | 35 | 140 | 35 | 105 | 21 | 42 | 7 | 7 | 041 | D7/A6 = 64*7!/7! = 64 | |
A4A1A1 | { } | f1 | 2 | 672 | 10 | 5 | 20 | 10 | 20 | 10 | 10 | 5 | 2 | { }×{3,3,3} | D7/A4A1A1 = 64*7!/5!/2/2 = 672 | |
A3A2 | 100 | f2 | 3 | 3 | 2240 | 1 | 4 | 4 | 6 | 6 | 4 | 4 | 1 | {3,3}v( ) | D7/A3A2 = 64*7!/4!/3! = 2240 | |
A3A3 | 101 | f3 | 4 | 6 | 4 | 560 | * | 4 | 0 | 6 | 0 | 4 | 0 | {3,3} | D7/A3A3 = 64*7!/4!/4! = 560 | |
A3A2 | 110 | 4 | 6 | 4 | * | 2240 | 1 | 3 | 3 | 3 | 3 | 1 | {3}v( ) | D7/A3A2 = 64*7!/4!/3! = 2240 | ||
D4A2 | 111 | f4 | 8 | 24 | 32 | 8 | 8 | 280 | * | 3 | 0 | 3 | 0 | {3} | D7/D4A2 = 64*7!/8/4!/2 = 280 | |
A4A1 | 120 | 5 | 10 | 10 | 0 | 5 | * | 1344 | 1 | 2 | 2 | 1 | { }v( ) | D7/A4A1 = 64*7!/5!/2 = 1344 | ||
D5A1 | 121 | f5 | 16 | 80 | 160 | 40 | 80 | 10 | 16 | 84 | * | 2 | 0 | { } | D7/D5A1 = 64*7!/16/5!/2 = 84 | |
A5 | 130 | 6 | 15 | 20 | 0 | 15 | 0 | 6 | * | 448 | 1 | 1 | D7/A5 = 64*7!/6! = 448 | |||
D6 | 131 | f6 | 32 | 240 | 640 | 160 | 480 | 60 | 192 | 12 | 32 | 14 | * | ( ) | D7/D6 = 64*7!/32/6! = 14 | |
A6 | 140 | 7 | 21 | 35 | 0 | 35 | 0 | 21 | 0 | 7 | * | 64 | D7/A6 = 64*7!/7! = 64 |
There are 95 uniform polytopes with D6 symmetry, 63 are shared by the B6 symmetry, and 32 are unique:
In five-dimensional geometry, a 5-cube is a name for a five-dimensional hypercube with 32 vertices, 80 edges, 80 square faces, 40 cubic cells, and 10 tesseract 4-faces.
In five-dimensional geometry, a demipenteract or 5-demicube is a semiregular 5-polytope, constructed from a 5-hypercube (penteract) with alternated vertices removed.
In geometry, a 6-demicube or demihexeract is a uniform 6-polytope, constructed from a 6-cube (hexeract) with alternated vertices removed. It is part of a dimensionally infinite family of uniform polytopes called demihypercubes.
In geometry, a 7-cube is a seven-dimensional hypercube with 128 vertices, 448 edges, 672 square faces, 560 cubic cells, 280 tesseract 4-faces, 84 penteract 5-faces, and 14 hexeract 6-faces.
In geometry, a demiocteract or 8-demicube is a uniform 8-polytope, constructed from the 8-hypercube, octeract, with alternated vertices removed. It is part of a dimensionally infinite family of uniform polytopes called demihypercubes.
In geometry, a demienneract or 9-demicube is a uniform 9-polytope, constructed from the 9-cube, with alternated vertices removed. It is part of a dimensionally infinite family of uniform polytopes called demihypercubes.
In geometry, an 8-cube is an eight-dimensional hypercube. It has 256 vertices, 1024 edges, 1792 square faces, 1792 cubic cells, 1120 tesseract 4-faces, 448 5-cube 5-faces, 112 6-cube 6-faces, and 16 7-cube 7-faces.
In geometry, a 9-cube is a nine-dimensional hypercube with 512 vertices, 2304 edges, 4608 square faces, 5376 cubic cells, 4032 tesseract 4-faces, 2016 5-cube 5-faces, 672 6-cube 6-faces, 144 7-cube 7-faces, and 18 8-cube 8-faces.
In geometry, a 6-simplex is a self-dual regular 6-polytope. It has 7 vertices, 21 edges, 35 triangle faces, 35 tetrahedral cells, 21 5-cell 4-faces, and 7 5-simplex 5-faces. Its dihedral angle is cos−1(1/6), or approximately 80.41°.
In geometry, an 8-orthoplex or 8-cross polytope is a regular 8-polytope with 16 vertices, 112 edges, 448 triangle faces, 1120 tetrahedron cells, 1792 5-cells 4-faces, 1792 5-faces, 1024 6-faces, and 256 7-faces.
In geometry, a 10-cube is a ten-dimensional hypercube. It has 1024 vertices, 5120 edges, 11520 square faces, 15360 cubic cells, 13440 tesseract 4-faces, 8064 5-cube 5-faces, 3360 6-cube 6-faces, 960 7-cube 7-faces, 180 8-cube 8-faces, and 20 9-cube 9-faces.
In five-dimensional geometry, a rectified 5-simplex is a convex uniform 5-polytope, being a rectification of the regular 5-simplex.
In geometry, a 10-demicube or demidekeract is a uniform 10-polytope, constructed from the 10-cube with alternated vertices removed. It is part of a dimensionally infinite family of uniform polytopes called demihypercubes.
In six-dimensional geometry, a runcic 5-cube or is a convex uniform 5-polytope. There are 2 runcic forms for the 5-cube. Runcic 5-cubes have half the vertices of runcinated 5-cubes.
In seven-dimensional geometry, a cantic 7-cube or truncated 7-demicube as a uniform 7-polytope, being a truncation of the 7-demicube.
In six-dimensional geometry, a steric 6-cube is a convex uniform 6-polytope. There are unique 4 steric forms of the 6-cube.
In six-dimensional geometry, a pentic 6-cube is a convex uniform 6-polytope.
In seven-dimensional geometry, a runcic 7-cube is a convex uniform 7-polytope, related to the uniform 7-demicube. There are 2 unique forms.
In seven-dimensional geometry, a hexic 7-cube is a convex uniform 7-polytope, constructed from the uniform 7-demicube. There are 16 unique forms.
In seven-dimensional geometry, a stericated 7-cube is a convex uniform 7-polytope, being a runcination of the uniform 7-demicube. There are 4 unique runcinations for the 7-demicube including truncation and cantellation.