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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}.

Contents

Family membersEdit

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)

ElementsEdit

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 alsoEdit

ReferencesEdit

  • 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

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
Fundamental convex regular and uniform honeycombs in dimensions 2-9
          /   /  
{3[3]} δ3 3 3 Hexagonal
{3[4]} δ4 4 4
{3[5]} δ5 5 5 24-cell honeycomb
{3[6]} δ6 6 6
{3[7]} δ7 7 7 222
{3[8]} δ8 8 8 133331
{3[9]} δ9 9 9 152251521
{3[10]} δ10 10 10
{3[n]} δn n n 1k22k1k21