9-demicube

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Demienneract
(9-demicube)
Demienneract ortho petrie.svg
Petrie polygon
TypeUniform 9-polytope
Family demihypercube
Coxeter symbol 161
Schläfli symbol {3,36,1} = h{4,37}
s{21,1,1,1,1,1,1,1}
Coxeter-Dynkin diagram CDel nodes 10ru.pngCDel split2.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.png = CDel node h1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.png
CDel node h.pngCDel 2c.pngCDel node h.pngCDel 2c.pngCDel node h.pngCDel 2c.pngCDel node h.pngCDel 2c.pngCDel node h.pngCDel 2c.pngCDel node h.pngCDel 2c.pngCDel node h.pngCDel 2c.pngCDel node h.pngCDel 2c.pngCDel node h.png
8-faces27418 {31,5,1} Demiocteract ortho petrie.svg
256 {37} 8-simplex t0.svg
7-faces2448144 {31,4,1} Demihepteract ortho petrie.svg
2304 {36} 7-simplex t0.svg
6-faces9888672 {31,3,1} Demihexeract ortho petrie.svg
9216 {35} 6-simplex t0.svg
5-faces235202016 {31,2,1} Demipenteract graph ortho.svg
21504 {34} 5-simplex t0.svg
4-faces362884032 {31,1,1} Cross graph 4.svg
32256 {33} 4-simplex t0.svg
Cells376325376 {31,0,1} 3-simplex t0.svg
32256 {3,3} 3-simplex t0.svg
Faces21504 {3} 2-simplex t0.svg
Edges4608
Vertices256
Vertex figure Rectified 8-simplex
8-simplex t1.svg
Symmetry group D9, [36,1,1] = [1+,4,37]
[28]+
Dual?
Properties convex

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.

Contents

E. L. Elte identified it in 1912 as a semiregular polytope, labeling it as HM9 for a 9-dimensional half measure polytope.

Coxeter named this polytope as 161 from its Coxeter diagram, with a ring on one of the 1-length branches, CDel node 1.pngCDel 3.pngCDel node.pngCDel split1.pngCDel nodes.pngCDel 3a.pngCDel nodea.pngCDel 3a.pngCDel nodea.pngCDel 3a.pngCDel nodea.pngCDel 3a.pngCDel nodea.pngCDel 3a.pngCDel nodea.png and Schläfli symbol or {3,36,1}.

Cartesian coordinates

Cartesian coordinates for the vertices of a demienneract centered at the origin are alternate halves of the enneract:

(±1,±1,±1,±1,±1,±1,±1,±1,±1)

with an odd number of plus signs.

Images

orthographic projections
Coxeter plane B9D9D8
Graph 9-demicube t0 B9.svg 9-demicube t0 D9.svg 9-demicube t0 D8.svg
Dihedral symmetry [18]+ = [9][16][14]
Graph 9-demicube t0 D7.svg 9-demicube t0 D6.svg
Coxeter planeD7D6
Dihedral symmetry[12][10]
Coxeter groupD5D4D3
Graph 9-demicube t0 D5.svg 9-demicube t0 D4.svg 9-demicube t0 D3.svg
Dihedral symmetry[8][6][4]
Coxeter planeA7A5A3
Graph 9-demicube t0 A7.svg 9-demicube t0 A5.svg 9-demicube t0 A3.svg
Dihedral symmetry[8][6][4]

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References

Family An Bn I2(p) / Dn E6 / E7 / E8 / F4 / G2 Hn
Regular polygon Triangle Square p-gon Hexagon Pentagon
Uniform polyhedron Tetrahedron OctahedronCube Demicube DodecahedronIcosahedron
Uniform polychoron Pentachoron 16-cellTesseract Demitesseract 24-cell 120-cell600-cell
Uniform 5-polytope 5-simplex 5-orthoplex5-cube 5-demicube
Uniform 6-polytope 6-simplex 6-orthoplex6-cube 6-demicube 122221
Uniform 7-polytope 7-simplex 7-orthoplex7-cube 7-demicube 132231321
Uniform 8-polytope 8-simplex 8-orthoplex8-cube 8-demicube 142241421
Uniform 9-polytope 9-simplex 9-orthoplex9-cube 9-demicube
Uniform 10-polytope 10-simplex 10-orthoplex10-cube 10-demicube
Uniform n-polytope n-simplex n-orthoplexn-cube n-demicube 1k22k1k21 n-pentagonal polytope
Topics: Polytope familiesRegular polytopeList of regular polytopes and compounds