Rectified 7-orthoplexes

  (Redirected from Birectified 7-orthoplex)
7-cube t6.svg
7-orthoplex
CDel node 1.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node.png
7-cube t5.svg
Rectified 7-orthoplex
CDel node.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node.png
7-cube t4.svg
Birectified 7-orthoplex
CDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node.png
7-cube t3.svg
Trirectified 7-orthoplex
CDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node.png
7-cube t2.svg
Birectified 7-cube
CDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node.png
7-cube t1.svg
Rectified 7-cube
CDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node 1.pngCDel 4.pngCDel node.png
7-cube t0.svg
7-cube
CDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node 1.png
Orthogonal projections in B7 Coxeter plane

In seven-dimensional geometry, a rectified 7-orthoplex is a convex uniform 7-polytope, being a rectification of the regular 7-orthoplex.

There are unique 7 degrees of rectifications, the zeroth being the 7-orthoplex, and the 6th and last being the 7-cube. Vertices of the rectified 7-orthoplex are located at the edge-centers of the 7-orthoplex. Vertices of the birectified 7-orthoplex are located in the triangular face centers of the 7-orthoplex. Vertices of the trirectified 7-orthoplex are located in the tetrahedral cell centers of the 7-orthoplex.

Rectified 7-orthoplexEdit

Rectified 7-orthoplex
Type uniform 7-polytope
Schläfli symbol r{3,3,3,3,3,4}
Coxeter-Dynkin diagrams              
           
6-faces 142
5-faces 1344
4-faces 3360
Cells 3920
Faces 2520
Edges 840
Vertices 84
Vertex figure 5-orthoplex prism
Coxeter groups B7, [3,3,3,3,3,4]
D7, [34,1,1]
Properties convex

The rectified 7-orthoplex is the vertex figure for the demihepteractic honeycomb. The rectified 7-orthoplex's 84 vertices represent the kissing number of a sphere-packing constructed from this honeycomb.

            or              

Alternate namesEdit

  • rectified heptacross
  • rectified hecatonicosoctaexon (Acronym rez) (Jonathan Bowers) - rectified 128-faceted polyexon[1]

ImagesEdit

orthographic projections
Coxeter plane B7 / A6 B6 / D7 B5 / D6 / A4
Graph      
Dihedral symmetry [14] [12] [10]
Coxeter plane B4 / D5 B3 / D4 / A2 B2 / D3
Graph      
Dihedral symmetry [8] [6] [4]
Coxeter plane A5 A3
Graph    
Dihedral symmetry [6] [4]

ConstructionEdit

There are two Coxeter groups associated with the rectified heptacross, one with the C7 or [4,3,3,3,3,3] Coxeter group, and a lower symmetry with two copies of pentacross facets, alternating, with the D7 or [34,1,1] Coxeter group.

Cartesian coordinatesEdit

Cartesian coordinates for the vertices of a rectified heptacross, centered at the origin, edge length   are all permutations of:

(±1,±1,0,0,0,0,0)

Root vectorsEdit

Its 84 vertices represent the root vectors of the simple Lie group D7. The vertices can be seen in 3 hyperplanes, with the 21 vertices rectified 6-simplexs cells on opposite sides, and 42 vertices of an expanded 6-simplex passing through the center. When combined with the 14 vertices of the 7-orthoplex, these vertices represent the 98 root vectors of the B7 and C7 simple Lie groups.

Birectified 7-orthoplexEdit

Birectified 7-orthoplex
Type uniform 7-polytope
Schläfli symbol 2r{3,3,3,3,3,4}
Coxeter-Dynkin diagrams              
           
6-faces 142
5-faces 1428
4-faces 6048
Cells 10640
Faces 8960
Edges 3360
Vertices 280
Vertex figure {3}×{3,3,4}
Coxeter groups B7, [3,3,3,3,3,4]
D7, [34,1,1]
Properties convex

Alternate namesEdit

  • Birectified heptacross
  • Birectified hecatonicosoctaexon (Acronym barz) (Jonathan Bowers) - birectified 128-faceted polyexon[2]

ImagesEdit

orthographic projections
Coxeter plane B7 / A6 B6 / D7 B5 / D6 / A4
Graph      
Dihedral symmetry [14] [12] [10]
Coxeter plane B4 / D5 B3 / D4 / A2 B2 / D3
Graph      
Dihedral symmetry [8] [6] [4]
Coxeter plane A5 A3
Graph    
Dihedral symmetry [6] [4]

Cartesian coordinatesEdit

Cartesian coordinates for the vertices of a birectified 7-orthoplex, centered at the origin, edge length   are all permutations of:

(±1,±1,±1,0,0,0,0)

Trirectified 7-orthoplexEdit

A trirectified 7-orthoplex is the same as a trirectified 7-cube.

NotesEdit

  1. ^ Klitzing, (o3o3x3o3o3o4o - rez)
  2. ^ Klitzing, (o3o3x3o3o3o4o - barz)

ReferencesEdit

  • 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]
  • Norman Johnson Uniform Polytopes, Manuscript (1991)
    • N.W. Johnson: The Theory of Uniform Polytopes and Honeycombs, Ph.D.
  • Klitzing, Richard. "7D uniform polytopes (polyexa)". o3x3o3o3o3o4o - rez, o3o3x3o3o3o4o - barz

External linksEdit

Fundamental convex regular and uniform polytopes in dimensions 2–10
An Bn I2(p) / Dn E6 / E7 / E8 / F4 / G2 Hn
Triangle Square p-gon Hexagon Pentagon
Tetrahedron OctahedronCube Demicube DodecahedronIcosahedron
5-cell 16-cellTesseract Demitesseract 24-cell 120-cell600-cell
5-simplex 5-orthoplex5-cube 5-demicube
6-simplex 6-orthoplex6-cube 6-demicube 122221
7-simplex 7-orthoplex7-cube 7-demicube 132231321
8-simplex 8-orthoplex8-cube 8-demicube 142241421
9-simplex 9-orthoplex9-cube 9-demicube
10-simplex 10-orthoplex10-cube 10-demicube
n-simplex n-orthoplexn-cube n-demicube 1k22k1k21 n-pentagonal polytope
Topics: Polytope familiesRegular polytopeList of regular polytopes and compounds