Rectified 8-orthoplexes#Rectified 8-orthoplex

class=wikitable align=right width=400 style="margin-left:1em;"
align=center

|100px
8-orthoplex
{{CDD|node_1|3|node|3|node|3|node|3|node|3|node|3|node|4|node}}

|100px
Rectified 8-orthoplex
{{CDD|node|3|node_1|3|node|3|node|3|node|3|node|3|node|4|node}}

|100px
Birectified 8-orthoplex
{{CDD|node|3|node|3|node_1|3|node|3|node|3|node|3|node|4|node}}

|100px
Trirectified 8-orthoplex
{{CDD|node|3|node|3|node|3|node_1|3|node|3|node|3|node|4|node}}

align=center

|100px
Trirectified 8-cube
{{CDD|node|3|node|3|node|3|node|3|node_1|3|node|3|node|4|node}}

|100px
Birectified 8-cube
{{CDD|node|3|node|3|node|3|node|3|node|3|node_1|3|node|4|node}}

|100px
Rectified 8-cube
{{CDD|node|3|node|3|node|3|node|3|node|3|node|3|node_1|4|node}}

|100px
8-cube
{{CDD|node|3|node|3|node|3|node|3|node|3|node|3|node|4|node_1}}

colspan=4|Orthogonal projections in A8 Coxeter plane

In eight-dimensional geometry, a rectified 8-orthoplex is a convex uniform 8-polytope, being a rectification of the regular 8-orthoplex.

There are unique 8 degrees of rectifications, the zeroth being the 8-orthoplex, and the 7th and last being the 8-cube. Vertices of the rectified 8-orthoplex are located at the edge-centers of the 8-orthoplex. Vertices of the birectified 8-orthoplex are located in the triangular face centers of the 8-orthoplex. Vertices of the trirectified 8-orthoplex are located in the tetrahedral cell centers of the 8-orthoplex.

Rectified 8-orthoplex

class="wikitable" align="right" style="margin-left:10px" width="250"

!bgcolor=#e7dcc3 colspan=2|Rectified 8-orthoplex

bgcolor=#e7dcc3|Typeuniform 8-polytope
bgcolor=#e7dcc3|Schläfli symbolt1{3,3,3,3,3,3,4}
bgcolor=#e7dcc3|Coxeter-Dynkin diagrams{{CDD|node|3|node_1|3|node|3|node|3|node|3|node|3|node|4|node}}
{{CDD|node|3|node_1|3|node|3|node|3|node|3|node|split1|nodes}}
bgcolor=#e7dcc3|7-faces272
bgcolor=#e7dcc3|6-faces3072
bgcolor=#e7dcc3|5-faces8960
bgcolor=#e7dcc3|4-faces12544
bgcolor=#e7dcc3|Cells10080
bgcolor=#e7dcc3|Faces4928
bgcolor=#e7dcc3|Edges1344
bgcolor=#e7dcc3|Vertices112
bgcolor=#e7dcc3|Vertex figure6-orthoplex prism
bgcolor=#e7dcc3|Petrie polygonhexakaidecagon
bgcolor=#e7dcc3|Coxeter groupsC8, [4,36]
D8, [35,1,1]
bgcolor=#e7dcc3|Propertiesconvex

The rectified 8-orthoplex has 112 vertices. These represent the root vectors of the simple Lie group D8. The vertices can be seen in 3 hyperplanes, with the 28 vertices rectified 7-simplexs cells on opposite sides, and 56 vertices of an expanded 7-simplex passing through the center. When combined with the 16 vertices of the 8-orthoplex, these vertices represent the 128 root vectors of the B8 and C8 simple Lie groups.

= Related polytopes =

The rectified 8-orthoplex is the vertex figure for the demiocteractic honeycomb.

: {{CDD|nodes_10ru|split2|node|3|node|3|node|3|node|3|node|split1|nodes}} or {{CDD|nodes_10ru|split2|node|3|node|3|node|3|node|3|node|3|node|4|node}}

= Alternate names=

  • rectified octacross
  • rectified diacosipentacontahexazetton (Acronym: rek) (Jonathan Bowers)Klitzing, (o3x3o3o3o3o3o4o - rek)

= Construction =

There are two Coxeter groups associated with the rectified 8-orthoplex, one with the C8 or [4,36] Coxeter group, and a lower symmetry with two copies of heptcross facets, alternating, with the D8 or [35,1,1] Coxeter group.

= Cartesian coordinates =

Cartesian coordinates for the vertices of a rectified 8-orthoplex, centered at the origin, edge length \sqrt{2} are all permutations of:

: (±1,±1,0,0,0,0,0,0)

= Images =

{{8-cube Coxeter plane graphs|t6|150}}

Birectified 8-orthoplex

class="wikitable" align="right" style="margin-left:10px" width="250"

!bgcolor=#e7dcc3 colspan=2|Birectified 8-orthoplex

bgcolor=#e7dcc3|Typeuniform 8-polytope
bgcolor=#e7dcc3|Schläfli symbolt2{3,3,3,3,3,3,4}
bgcolor=#e7dcc3|Coxeter-Dynkin diagrams{{CDD|node|3|node|3|node_1|3|node|3|node|3|node|3|node|4|node}}
{{CDD|node|3|node|3|node_1|3|node|3|node|3|node|split1|nodes}}
bgcolor=#e7dcc3|7-faces272
bgcolor=#e7dcc3|6-faces3184
bgcolor=#e7dcc3|5-faces16128
bgcolor=#e7dcc3|4-faces34048
bgcolor=#e7dcc3|Cells36960
bgcolor=#e7dcc3|Faces22400
bgcolor=#e7dcc3|Edges6720
bgcolor=#e7dcc3|Vertices448
bgcolor=#e7dcc3|Vertex figure{3,3,3,4}x{3}
bgcolor=#e7dcc3|Coxeter groupsC8, [3,3,3,3,3,3,4]
D8, [35,1,1]
bgcolor=#e7dcc3|Propertiesconvex

= Alternate names=

  • birectified octacross
  • birectified diacosipentacontahexazetton (Acronym: bark) (Jonathan Bowers)Klitzing, (o3o3x3o3o3o3o4o - bark)

= Cartesian coordinates =

Cartesian coordinates for the vertices of a birectified 8-orthoplex, centered at the origin, edge length \sqrt{2} are all permutations of:

: (±1,±1,±1,0,0,0,0,0)

= Images =

{{8-cube Coxeter plane graphs|t5|150}}

Trirectified 8-orthoplex

class="wikitable" align="right" style="margin-left:10px" width="250"

!bgcolor=#e7dcc3 colspan=2|Trirectified 8-orthoplex

bgcolor=#e7dcc3|Typeuniform 8-polytope
bgcolor=#e7dcc3|Schläfli symbolt3{3,3,3,3,3,3,4}
bgcolor=#e7dcc3|Coxeter-Dynkin diagrams{{CDD|node|3|node|3|node|3|node_1|3|node|3|node|3|node|4|node}}
{{CDD|node|3|node|3|node|3|node_1|3|node|3|node|split1|nodes}}
bgcolor=#e7dcc3|7-faces16+256
bgcolor=#e7dcc3|6-faces1024 + 2048 + 112
bgcolor=#e7dcc3|5-faces1792 + 7168 + 7168 + 448
bgcolor=#e7dcc3|4-faces1792 + 10752 + 21504 + 14336
bgcolor=#e7dcc3|Cells8960 + 126880 + 35840
bgcolor=#e7dcc3|Faces17920 + 35840
bgcolor=#e7dcc3|Edges17920
bgcolor=#e7dcc3|Vertices1120
bgcolor=#e7dcc3|Vertex figure{3,3,4}x{3,3}
bgcolor=#e7dcc3|Coxeter groupsC8, [3,3,3,3,3,3,4]
D8, [35,1,1]
bgcolor=#e7dcc3|Propertiesconvex

The trirectified 8-orthoplex can tessellate space in the quadrirectified 8-cubic honeycomb.

= Alternate names=

  • trirectified octacross
  • trirectified diacosipentacontahexazetton (acronym: tark) (Jonathan Bowers)Klitzing, (o3o3o3x3o3o3o4o - tark)

= Cartesian coordinates =

Cartesian coordinates for the vertices of a trirectified 8-orthoplex, centered at the origin, edge length \sqrt{2} are all permutations of:

: (±1,±1,±1,±1,0,0,0,0)

= Images =

{{8-cube Coxeter plane graphs|t4|150}}

Notes

{{reflist}}

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}} [http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471010030.html]
  • (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.
  • {{KlitzingPolytopes|polyzetta.htm|8D|uniform polytopes (polyzetta)}} o3x3o3o3o3o3o4o - rek, o3o3x3o3o3o3o4o - bark, o3o3o3x3o3o3o4o - tark