8-orthoplex Octacross | |
---|---|
Orthogonal projection inside Petrie polygon | |
Type | Regular 8-polytope |
Family | orthoplex |
Schläfli symbol | {36,4} {3,3,3,3,3,31,1} |
Coxeter-Dynkin diagrams | |
7-faces | 256 {36} |
6-faces | 1024 {35} |
5-faces | 1792 {34} |
4-faces | 1792 {33} |
Cells | 1120 {3,3} |
Faces | 448 {3} |
Edges | 112 |
Vertices | 16 |
Vertex figure | 7-orthoplex |
Petrie polygon | hexadecagon |
Coxeter groups | C8, [36,4] D8, [35,1,1] |
Dual | 8-cube |
Properties | convex, Hanner polytope |
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.
It has two constructive forms, the first being regular with Schläfli symbol {36,4}, and the second with alternately labeled (checkerboarded) facets, with Schläfli symbol {3,3,3,3,3,31,1} or Coxeter symbol 511.
It is a part of an infinite family of polytopes, called cross-polytopes or orthoplexes. The dual polytope is an 8-hypercube, or octeract.
This configuration matrix represents the 8-orthoplex. The rows and columns correspond to vertices, edges, faces, cells, 4-faces, 5-faces, 6-faces and 7-faces. The diagonal numbers say how many of each element occur in the whole 8-orthoplex. 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 individual mirrors. [3]
B8 | k-face | fk | f0 | f1 | f2 | f3 | f4 | f5 | f6 | f7 | k-figure | notes | |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
B7 | ( ) | f0 | 16 | 14 | 84 | 280 | 560 | 672 | 448 | 128 | {3,3,3,3,3,4} | B8/B7 = 2^8*8!/2^7/7! = 16 | |
A1B6 | { } | f1 | 2 | 112 | 12 | 60 | 160 | 240 | 192 | 64 | {3,3,3,3,4} | B8/A1B6 = 2^8*8!/2/2^6/6! = 112 | |
A2B5 | {3} | f2 | 3 | 3 | 448 | 10 | 40 | 80 | 80 | 32 | {3,3,3,4} | B8/A2B5 = 2^8*8!/3!/2^5/5! = 448 | |
A3B4 | {3,3} | f3 | 4 | 6 | 4 | 1120 | 8 | 24 | 32 | 16 | {3,3,4} | B8/A3B4 = 2^8*8!/4!/2^4/4! = 1120 | |
A4B3 | {3,3,3} | f4 | 5 | 10 | 10 | 5 | 1792 | 6 | 12 | 8 | {3,4} | B8/A4B3 = 2^8*8!/5!/8/3! = 1792 | |
A5B2 | {3,3,3,3} | f5 | 6 | 15 | 20 | 15 | 6 | 1792 | 4 | 4 | {4} | B8/A5B2 = 2^8*8!/6!/4/2 = 1792 | |
A6A1 | {3,3,3,3,3} | f6 | 7 | 21 | 35 | 35 | 21 | 7 | 1024 | 2 | { } | B8/A6A1 = 2^8*8!/7!/2 = 1024 | |
A7 | {3,3,3,3,3,3} | f7 | 8 | 28 | 56 | 70 | 56 | 28 | 8 | 256 | ( ) | B8/A7 = 2^8*8!/8! = 256 |
There are two Coxeter groups associated with the 8-cube, one regular, dual of the octeract with the C8 or [4,3,3,3,3,3,3] symmetry group, and a half symmetry with two copies of 7-simplex facets, alternating, with the D8 or [35,1,1] symmetry group. A lowest symmetry construction is based on a dual of an 8-orthotope, called an 8-fusil.
Name | Coxeter diagram | Schläfli symbol | Symmetry | Order | Vertex figure |
---|---|---|---|---|---|
regular 8-orthoplex | {3,3,3,3,3,3,4} | [3,3,3,3,3,3,4] | 10321920 | ||
Quasiregular 8-orthoplex | {3,3,3,3,3,31,1} | [3,3,3,3,3,31,1] | 5160960 | ||
8-fusil | 8{} | [27] | 256 |
Cartesian coordinates for the vertices of an 8-cube, centered at the origin are
Every vertex pair is connected by an edge, except opposites.
B8 | B7 | ||||
---|---|---|---|---|---|
[16] | [14] | ||||
B6 | B5 | ||||
[12] | [10] | ||||
B4 | B3 | B2 | |||
[8] | [6] | [4] | |||
A7 | A5 | A3 | |||
[8] | [6] | [4] |
It is used in its alternated form 511 with the 8-simplex to form the 521 honeycomb.
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 5-orthoplex, or 5-cross polytope, is a five-dimensional polytope with 10 vertices, 40 edges, 80 triangle faces, 80 tetrahedron cells, 32 5-cell 4-faces.
In geometry, a 6-cube is a six-dimensional hypercube with 64 vertices, 192 edges, 240 square faces, 160 cubic cells, 60 tesseract 4-faces, and 12 5-cube 5-faces.
In geometry, a 6-orthoplex, or 6-cross polytope, is a regular 6-polytope with 12 vertices, 60 edges, 160 triangle faces, 240 tetrahedron cells, 192 5-cell 4-faces, and 64 5-faces.
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, 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 7-orthoplex, or 7-cross polytope, is a regular 7-polytope with 14 vertices, 84 edges, 280 triangle faces, 560 tetrahedron cells, 672 5-cells 4-faces, 448 5-faces, and 128 6-faces.
In geometry, a 9-orthoplex or 9-cross polytope, is a regular 9-polytope with 18 vertices, 144 edges, 672 triangle faces, 2016 tetrahedron cells, 4032 5-cells 4-faces, 5376 5-simplex 5-faces, 4608 6-simplex 6-faces, 2304 7-simplex 7-faces, and 512 8-simplex 8-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 geometry, a 10-orthoplex or 10-cross polytope, is a regular 10-polytope with 20 vertices, 180 edges, 960 triangle faces, 3360 octahedron cells, 8064 5-cells 4-faces, 13440 5-faces, 15360 6-faces, 11520 7-faces, 5120 8-faces, and 1024 9-faces.
In 8-dimensional geometry, the 241 is a uniform 8-polytope, constructed within the symmetry of the E8 group.
In 6-dimensional geometry, the 221 polytope is a uniform 6-polytope, constructed within the symmetry of the E6 group. It was discovered by Thorold Gosset, published in his 1900 paper. He called it an 6-ic semi-regular figure. It is also called the Schläfli polytope.
In six-dimensional geometry, a pentellated 6-simplex is a convex uniform 6-polytope with 5th order truncations of the regular 6-simplex.
In five-dimensional geometry, a rectified 5-orthoplex is a convex uniform 5-polytope, being a rectification of the regular 5-orthoplex.
In seven-dimensional geometry, a rectified 7-orthoplex is a convex uniform 7-polytope, being a rectification of the regular 7-orthoplex.
In eight-dimensional geometry, a rectified 8-orthoplex is a convex uniform 8-polytope, being a rectification of the regular 8-orthoplex.
In six-dimensional geometry, a truncated 6-orthoplex is a convex uniform 6-polytope, being a truncation of the regular 6-orthoplex.
In six-dimensional geometry, a truncated 6-simplex is a convex uniform 6-polytope, being a truncation of the regular 6-simplex.
In seven-dimensional geometry, a runcinated 7-simplex is a convex uniform 7-polytope with 3rd order truncations (runcination) of the regular 7-simplex.