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Uniform 2 k1 polytope

In geometry, 2k1 polytope is a uniform polytope in n dimensions (n = k+4) constructed from the En Coxeter group. The family was named by their Coxeter symbol as 2k1 by its bifurcating Coxeter-Dynkin diagram, with a single ring on the end of the 2-node sequence. It can be named by an extended Schläfli symbol {3,3,3k,1}.

Family members

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The family starts uniquely as 6-polytopes, but can be extended backwards to include the 5-orthoplex (pentacross) in 5-dimensions, and the 4-simplex (5-cell) in 4-dimensions.

Each polytope is constructed from (n-1)-simplex and 2k-1,1 (n-1)-polytope facets, each has a vertex figure as an (n-1)-demicube, {31,n-2,1}.

The sequence ends with k=6 (n=10), as an infinite hyperbolic tessellation of 9-space.

The complete family of 2k1 polytope polytopes are:

  1. 5-cell: 201, (5 tetrahedra cells)
  2. Pentacross: 211, (32 5-cell (201) facets)
  3. 221, (72 5-simplex and 27 5-orthoplex (211) facets)
  4. 231, (576 6-simplex and 56 221 facets)
  5. 241, (17280 7-simplex and 240 231 facets)
  6. 251, tessellates Euclidean 8-space (∞ 8-simplex and ∞ 241 facets)
  7. 261, tessellates hyperbolic 9-space (∞ 9-simplex and ∞ 251 facets)

Elements

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Gosset 2k1 figures
n 2k1 Petrie
polygon
projection 		Name
Coxeter-Dynkin
diagram 		Facets Elements
2k-1,1 polytope (n-1)-simplex Vertices Edges Faces Cells 4-faces 5-faces 6-faces 7-faces
4 201   5-cell
     
{32,0,1} 		-- 5
{33}
  		5 10 10
  		5        
5 211   pentacross
       
{32,1,1} 		16
{32,0,1}
  		16
{34}
  		10 40 80
  		80
  		32
  		     
6 221   2 21 polytope
         
{32,2,1} 		27
{32,1,1}
  		72
{35}
  		27 216 720
  		1080
  		648
  		99
   		   
7 231   2 31 polytope
           
{32,3,1} 		56
{32,2,1}
  		576
{36}
  		126 2016 10080
  		20160
  		16128
  		4788
   		632
   		 
8 241   2 41 polytope
             
{32,4,1} 		240
{32,3,1}
  		17280
{37}
  		2160 69120 483840
  		1209600
  		1209600
  		544320
   		144960
   		17520
  
9 251 2 51 honeycomb
               
(8-space tessellation)
{32,5,1} 		∞
{32,4,1}
  		∞
{38}
  		∞
10 261 2 61 honeycomb
                 
(9-space tessellation)
{32,6,1} 		∞
{32,5,1} 		∞
{39}
  		∞

See also

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References

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  • Alicia Boole Stott Geometrical deduction of semiregular from regular polytopes and space fillings, Verhandelingen of the Koninklijke academy van Wetenschappen width unit Amsterdam, Eerste Sectie 11,1, Amsterdam, 1910
    • Stott, A. B. "Geometrical Deduction of Semiregular from Regular Polytopes and Space Fillings." Verhandelingen der Koninklijke Akad. Wetenschappen Amsterdam 11, 3-24, 1910.
    • Alicia Boole Stott, "Geometrical deduction of semiregular from regular polytopes and space fillings," Verhandelingen der Koninklijke Akademie van Wetenschappen te Amsterdam, (eerste sectie), Vol. 11, No. 1, pp. 1–24 plus 3 plates, 1910.
    • Stott, A. B. 1910. "Geometrical Deduction of Semiregular from Regular Polytopes and Space Fillings." Verhandelingen der Koninklijke Akad. Wetenschappen Amsterdam
  • Schoute, P. H., Analytical treatment of the polytopes regularly derived from the regular polytopes, Ver. der Koninklijke Akad. van Wetenschappen te Amsterdam (eerstie sectie), vol 11.5, 1913.
  • H. S. M. Coxeter: Regular and Semi-Regular Polytopes, Part I, Mathematische Zeitschrift, Springer, Berlin, 1940
  • N.W. Johnson: The Theory of Uniform Polytopes and Honeycombs, Ph.D. Dissertation, University of Toronto, 1966
  • H.S.M. Coxeter: Regular and Semi-Regular Polytopes, Part II, Mathematische Zeitschrift, Springer, Berlin, 1985
  • H.S.M. Coxeter: Regular and Semi-Regular Polytopes, Part III, Mathematische Zeitschrift, Springer, Berlin, 1988
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Fundamental convex regular and uniform polytopes in dimensions 2–10
Family An Bn I2(p) / Dn E6 / E7 / E8 / F4 / G2 Hn
Regular polygon Triangle Square p-gon Hexagon Pentagon
Uniform polyhedron Tetrahedron Octahedron • Cube Demicube Dodecahedron • Icosahedron
Uniform polychoron Pentachoron 16-cell • Tesseract Demitesseract 24-cell 120-cell • 600-cell
Uniform 5-polytope 5-simplex 5-orthoplex • 5-cube 5-demicube
Uniform 6-polytope 6-simplex 6-orthoplex • 6-cube 6-demicube 122 • 221
Uniform 7-polytope 7-simplex 7-orthoplex • 7-cube 7-demicube 132 • 231 • 321
Uniform 8-polytope 8-simplex 8-orthoplex • 8-cube 8-demicube 142 • 241 • 421
Uniform 9-polytope 9-simplex 9-orthoplex • 9-cube 9-demicube
Uniform 10-polytope 10-simplex 10-orthoplex • 10-cube 10-demicube
Uniform n-polytope n-simplex n-orthoplex • n-cube n-demicube 1k2 • 2k1 • k21 n-pentagonal polytope
Topics: Polytope families • Regular polytope • List of regular polytopes and compounds
Fundamental convex regular and uniform honeycombs in dimensions 2–9
Space Family           /   /  
E2 Uniform tiling 0[3] δ3 hδ3 qδ3 Hexagonal
E3 Uniform convex honeycomb 0[4] δ4 hδ4 qδ4
E4 Uniform 4-honeycomb 0[5] δ5 hδ5 qδ5 24-cell honeycomb
E5 Uniform 5-honeycomb 0[6] δ6 hδ6 qδ6
E6 Uniform 6-honeycomb 0[7] δ7 hδ7 qδ7 222
E7 Uniform 7-honeycomb 0[8] δ8 hδ8 qδ8 133 • 331
E8 Uniform 8-honeycomb 0[9] δ9 hδ9 qδ9 152 • 251 • 521
E9 Uniform 9-honeycomb 0[10] δ10 hδ10 qδ10
E10 Uniform 10-honeycomb 0[11] δ11 hδ11 qδ11
En-1 Uniform (n-1)-honeycomb 0[n] δn hδn qδn 1k2 • 2k1 • k21
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