5-orthoplex#Cartesian coordinates

{{Short description|Convex regular 5-polytope in geometry}}

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!bgcolor=#e7dcc3 colspan=2|Regular 5-orthoplex
Pentacross

bgcolor=#ffffff align=center colspan=2|281px
Orthogonal projection
inside Petrie polygon
bgcolor=#e7dcc3|TypeRegular 5-polytope
bgcolor=#e7dcc3|Familyorthoplex
bgcolor=#e7dcc3|Schläfli symbol{3,3,3,4}
{3,3,31,1}
bgcolor=#e7dcc3|Coxeter-Dynkin diagrams{{CDD|node_1|3|node|3|node|3|node|4|node}}
{{CDD|node_1|3|node|3|node|split1|nodes}}
bgcolor=#e7dcc3|4-faces32 {33} 25px
bgcolor=#e7dcc3|Cells80 {3,3} 25px
bgcolor=#e7dcc3|Faces80 {3}25px
bgcolor=#e7dcc3|Edges40
bgcolor=#e7dcc3|Vertices10
bgcolor=#e7dcc3|Vertex figure60px
16-cell
bgcolor=#e7dcc3|Petrie polygondecagon
bgcolor=#e7dcc3|Coxeter groupsBC5, [3,3,3,4]
D5, [32,1,1]
bgcolor=#e7dcc3|Dual5-cube
bgcolor=#e7dcc3|Propertiesconvex, Hanner polytope

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.

It has two constructed forms, the first being regular with Schläfli symbol {33,4}, and the second with alternately labeled (checkerboarded) facets, with Schläfli symbol {3,3,31,1} or Coxeter symbol 211.

It is a part of an infinite family of polytopes, called cross-polytopes or orthoplexes. The dual polytope is the 5-hypercube or 5-cube.

Alternate names

  • Pentacross, derived from combining the family name cross polytope with pente for five (dimensions) in Greek.
  • Triacontaditeron (or triacontakaiditeron) - as a 32-facetted 5-polytope (polyteron). Acronym: tac{{sfn|Klitzing|at=[https://bendwavy.org/klitzing/incmats/tac.htm (x3o3o3o4o - tac)]}}

As a configuration

This configuration matrix represents the 5-orthoplex. The rows and columns correspond to vertices, edges, faces, cells and 4-faces. The diagonal numbers say how many of each element occur in the whole 5-orthoplex. The nondiagonal numbers say how many of the column's element occur in or at the row's element.Coxeter, Regular Polytopes, sec 1.8 ConfigurationsCoxeter, Complex Regular Polytopes, p.117

\begin{bmatrix}\begin{matrix}

10 & 8 & 24 & 32 & 16 \\

2 & 40 & 6 & 12 & 8 \\

3 & 3 & 80 & 4 & 4 \\

4 & 6 & 4 & 80 & 2 \\

5 & 10 & 10 & 5 & 32

\end{matrix}\end{bmatrix}

Cartesian coordinates

Cartesian coordinates for the vertices of a 5-orthoplex, centered at the origin are

: (±1,0,0,0,0), (0,±1,0,0,0), (0,0,±1,0,0), (0,0,0,±1,0), (0,0,0,0,±1)

Construction

There are three Coxeter groups associated with the 5-orthoplex, one regular, dual of the penteract with the C5 or [4,3,3,3] Coxeter group, and a lower symmetry with two copies of 5-cell facets, alternating, with the D5 or [32,1,1] Coxeter group, and the final one as a dual 5-orthotope, called a 5-fusil which can have a variety of subsymmetries.

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!Name

!Coxeter diagram

!Schläfli symbol

!Symmetry

!Order

!Vertex figure(s)

align=center

!regular 5-orthoplex

|{{CDD|node_1|3|node|3|node|3|node|4|node}}

|{3,3,3,4}

|[3,3,3,4]

3840

|{{CDD|node_1|3|node|3|node|4|node}}

align=center

!Quasiregular 5-orthoplex

|{{CDD|node_1|3|node|3|node|split1|nodes}}

|{3,3,31,1}

|[3,3,31,1]

1920

|{{CDD|node_1|3|node|split1|nodes}}

align=center

!rowspan=8|5-fusil

align=center

|{{CDD|node_f1|4|node|3|node|3|node|3|node}}

{3,3,3,4}[4,3,3,3]3840{{CDD|node_f1|4|node|3|node|3|node}}
align=center

|{{CDD|node_f1|4|node|3|node|3|node|2|node_f1}}

{3,3,4}+{}[4,3,3,2]768{{CDD|node_f1|4|node|3|node|2|node_f1}}
align=center

|{{CDD|node_f1|4|node|3|node|2|node_f1|4|node}}

{3,4}+{4}[4,3,2,4]384{{CDD|node_f1|4|node|3|node|2|node_f1}}
{{CDD|node_f1|4|node|2|node_f1|4|node}}
align=center

|{{CDD|node_f1|4|node|3|node|2|node_f1|2|node_f1}}

{3,4}+2{}[4,3,2,2]192{{CDD|node_f1|4|node|3|node|2|node_f1}}
{{CDD|node_f1|4|node|2|node_f1|2|node_f1}}
align=center

|{{CDD|node_f1|4|node|2|node_f1|4|node|2|node_f1}}

2{4}+{}[4,2,4,2]128{{CDD|node_f1|4|node|2|node_f1|4|node}}
align=center

|{{CDD|node_f1|4|node|2|node_f1|2|node_f1|2|node_f1}}

{4}+3{}[4,2,2,2]64{{CDD|node_f1|4|node|2|node_f1|2|node_f1}}
{{CDD|node_f1|2|node_f1|2|node_f1|2|node_f1}}
align=center

|{{CDD|node_f1|2|node_f1|2|node_f1|2|node_f1|2|node_f1}}

|5{}

|[2,2,2,2]

32

|{{CDD|node_f1|2|node_f1|2|node_f1|2|node_f1}}

Other images

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

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|align=center|220px
The perspective projection (3D to 2D) of a stereographic projection (4D to 3D) of the Schlegel diagram (5D to 4D) of the 5-orthoplex. 10 sets of 4 edges form 10 circles in the 4D Schlegel diagram: two of these circles are straight lines in the stereographic projection because they contain the center of projection.

Related polytopes and honeycombs

{{2 k1 polytopes}}

This polytope is one of 31 uniform 5-polytopes generated from the B5 Coxeter plane, including the regular 5-cube and 5-orthoplex.

{{Penteract family}}

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, [https://www.wiley.com/en-us/Kaleidoscopes-p-9780471010036 wiley.com], {{isbn|978-0-471-01003-6}}
  • (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. (1966)
  • {{KlitzingPolytopes|polytera.htm|5D uniform polytopes (polytera) with acronyms}} x3o3o3o4o - tac {{sfn whitelist| CITEREFKlitzing}}