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List of regular polytopes

 
Wikipedia: List of regular polytopes

This page lists the regular polytopes in Euclidean, spherical and hyperbolic spaces.

The Schläfli symbol notation describes every regular polytope, and is used widely below as a compact reference name for each.

The regular polytopes are grouped by dimension and subgrouped by convex, nonconvex and infinite forms. Nonconvex forms use the same vertices as the convex forms, but have intersecting facets. Infinite forms tessellate a one lower dimensional Euclidean space.

Infinite forms can be extended to tessellate a hyperbolic space. Hyperbolic space is like normal space at a small scale, but parallel lines diverge at a distance. This allows vertex figures to have negative angle defects, like making a vertex with 7 equilateral triangles and allowing it to lie flat. It cannot be done in a regular plane, but can be at the right scale of a hyperbolic plane.

Contents

Overview

This table shows a summary of regular polytope counts by dimension

Dimension Convex Nonconvex Convex
Euclidean
tessellations
Convex
hyperbolic
tessellations
Nonconvex
hyperbolic
tessellations
Abstract
Polytopes
1 1 line segment 0 0 0 0 1
2 polygons star polygons 1 1 0
3 5 Platonic solids 4 Kepler-Poinsot solids 3 tilings
4 6 convex polychora 10 Schläfli-Hess polychora 1 honeycomb 4 0
5 3 convex 5-polytopes 0 nonconvex 5-polytopes 3 tessellations 5 4
6+ 3 0 1 0 0

Tessellations

The classical convex polytopes may be considered tessellations, or tilings, of spherical space. Tessellations of euclidean and hyperbolic space may also be considered regular polytopes. Note that an 'n'-dimensional polytope actually tessellates a space of one dimension less. For example, the (three dimensional) platonic solids tessellate the 'two'-dimensional 'surface' of the sphere.

One-dimensional regular polytope

There is only one polytope in 1 dimensions, whose boundaries are the two endpoints of a line segment, represented by the empty Schläfli symbol {}.

Two-dimensional regular polytopes

The two dimensional polytopes are called polygons. Regular polygons are equilateral and cyclic. A p-gonal regular polygon is represented by Schläfli symbol {p}.

Usually only convex polygons are considered regular, but star polygons, like the pentagram, can also be considered regular. They use the same vertices as the convex forms, but connect in an alternate connectivity which passes around the circle more than once to complete.

Star polygons should be called nonconvex rather than concave because the intersecting edges do not generate new vertices and all the vertices exist on a circle boundary.

Convex

The Schläfli symbol {p} represents a regular p-gon.

Name Triangle
(2-simplex)
Square
(2-orthoplex)
(2-cube)
Pentagon Hexagon Heptagon Octagon
Schläfli {3} {4} {5} {6} {7} {8}
Image Regular triangle.svg Kvadrato.svg Regular pentagon.svg Regular hexagon.svg Regular heptagon.svg Regular octagon.svg
Name Enneagon Decagon Hendecagon Dodecagon Triskaidecagon Tetradecagon
Schläfli {9} {10} {11} {12} {13} {14}
Image Regular nonagon.svg Regular decagon.svg Regular hendecagon.svg Regular dodecagon.svg Regular tridecagon.svg Regular tetradecagon.svg
Name Pentadecagon Hexadecagon Heptadecagon Octadecagon Enneadecagon Icosagon ...n-gon
Schläfli {15} {16} {17} {18} {19} {20} {n}
Image Regular pentadecagon.svg Regular hexadecagon.svg Regular heptadecagon.svg Regular octadecagon.svg Regular enneadecagon.svg Regular icosagon.svg


Degenerate (Spherical)

The regular henagon {1} and regular digon {2} can be considered degenerate regular polygons. They can exist nondegenerately in non-Euclidean spaces like on the surface of a sphere or torus.

Name Henagon Digon
Schläfli {1} {2}
Image Henagon.svg Digon.svg

Non-convex

There exist infinitely many non-convex regular polytopes in two dimensions, whose Schläfli symbols consist of rational numbers {n/m}. They are called star polygons and share the same vertex arrangements of the convex regular polygons.

In general, for any natural number n, there are n-pointed non-convex regular polygonal stars with Schläfli symbols {n/m} for all m such that m < n/2 (strictly speaking {n/m}={n/(n-m)}) and m and n are coprime.

Name Pentagram Heptagrams Octagram Enneagrams Decagram ...n-agrams
Schläfli {5/2} {7/2} {7/3} {8/3} {9/2} {9/4} {10/3} {n/m}
Image Star polygon 5-2.svg Star polygon 7-2.svg Star polygon 7-3.svg Star polygon 8-3.svg Star polygon 9-2.svg Star polygon 9-4.svg Star polygon 10-3.svg  

Tessellation

There is one tessellation of the line, giving one polytope, the (two-dimensional) apeirogon. This has infinitely many vertices and edges. Its Schläfli symbol is {∞}.

...Regular apeirogon.png...

Three-dimensional regular polytopes

In three dimensions, the regular polytopes are called polyhedra:

A regular polyhedron with Schläfli symbol {p,q} has a regular face type {p}, and regular vertex figure {q}.

A vertex figure (of a polyhedron) is a polygon, seen by connecting those vertices which are one edge away from a given vertex. For regular polyhedra, this vertex figure is always a regular (and planar) polygon.

Existence of a regular polyhedron {p,q} is constrained by an inequality, related to the vertex figure's angle defect:

1 / p + 1 / q > 1 / 2 : Polyhedron (existing in Euclidean 3-space)
1 / p + 1 / q = 1 / 2 : Euclidean plane tiling
1 / p + 1 / q < 1 / 2 : Hyperbolic plane tiling

By enumerating the permutations, we find 5 convex forms, 4 nonconvex forms and 3 plane tilings, all with polygons {p} and {q} limited to: {3},{4},{5}, {5/2}, and {6}.

Beyond Euclidean space, there is an infinite set of regular hyperbolic tilings.

Convex

The convex regular polyhedra are called the 5 Platonic solids. The vertex figure is given with each vertex count. All these polyhedra have a Euler characteristic (χ) of 2.

Name Schläfli
{p,q}
Image
(transparent)
Image
(solid)
Image
(sphere)
Faces
{p}
Edges Vertices
{q}
Symmetry Dual
Tetrahedron
(3-simplex)
(Pyramid)
{3,3} Tetrahedron.svg Tetrahedron.png Uniform tiling 332-t0.png 4
{3}
6 4
{3}
Td (self)
Cube
(3-cube)
(Hexahedron)
{4,3} Hexahedron.svg Hexahedron.png Uniform tiling 432-t0.png 6
{4}
12 8
{3}
Oh Octahedron
Octahedron
(3-orthoplex)
{3,4} Octahedron.svg Octahedron.png Uniform tiling 432-t2.png 8
{3}
12 6
{4}
Oh Cube
Dodecahedron {5,3} POV-Ray-Dodecahedron.svg Dodecahedron.png Uniform tiling 532-t0.png 12
{5}
30 20
{3}2
Ih Icosahedron
Icosahedron {3,5} Icosahedron.svg Icosahedron.png Uniform tiling 532-t2.png 20
{3}
30 12
{5}
Ih Dodecahedron

Degenerate (spherical)

In spherical geometry, the hosohedron {2,n} and dihedron {n,2} can be considered regular polyhedra (tilings of the sphere).

Some include:

Name Schläfli
{p,q}
Image
(sphere)
Faces
{p}
Edges Vertices
{q}
Symmetry Dual
Hengonal dihedron {1,2} Hengonal dihedron.png 2
{1}
1 1
{2}
C1v
(*22)
Hengonal hosohedron
Hengonal hosohedron {2,1} Digonal hosohedron.png 1
{2}
1 2
{1}
C1v
(*22)
Hengonal dihedron
Digonal dihedron
Digonal hosohedron
{2,2} Digonal dihedron.png 2
{2}
2 2
{2}
D2h
(*222)
Self
Trigonal hosohedron {2,3} Trigonal hosohedron.png 3
{2}
3 2
{3}
D3h
(*322)
Trigonal dihedron
Trigonal dihedron {3,2} Trigonal dihedron.png 2
{3}
3 3
{2}
D3h
(*322)
Trigonal hosohedron
Hexagonal hosohedron {2,6} Hexagonal hosohedron.png 6
{2}
6 2
{6}
D3h
(*622)
Hexagonal dihedron

Non-convex

The regular star polyhedra are called the Kepler-Poinsot polyhedra and there are four of them, based on the vertex arrangements of the dodecahedron {5,3} and icosahedron {3,5}:

As spherical tilings, these nonconvex forms overlap the sphere multiple times, called its density, being 3 or 7 for these forms. The tiling images show a single spherical polygon face in yellow.

Name Schläfli
{p,q}
Image
(transparent)
Image
(solid)
Image
(sphere)
Faces
{p}
Edges Vertices
{q}
χ Density Symmetry Dual
Small stellated dodecahedron {5/2,5} SmallStellatedDodecahedron.jpg Small stellated dodecahedron.png Small stellated dodecahedron tiling.png 12
{5/2}
30 12
{5}
-6 3 Ih Great dodecahedron
Great dodecahedron {5,5/2} GreatDodecahedron.jpg Great dodecahedron.png Great dodecahedron tiling.png 12
{5}
30 12
{5/2}
-6 3 Ih Small stellated dodecahedron
Great stellated dodecahedron {5/2,3} GreatStellatedDodecahedron.jpg Great stellated dodecahedron.png Great stellated dodecahedron tiling.png 12
{5/2}
30 20
{3}
2 7 Ih Great icosahedron
Great icosahedron {3,5/2} GreatIcosahedron.jpg Great icosahedron.png Great icosahedron tiling.png 20
{3}
30 12
{5/2}
2 7 Ih Great stellated dodecahedron

Tessellations

Euclidean tilings

There are three regular tessellations of the plane. All three have a Euler characteristic (χ) of 0.

Name Schläfli {p,q} Image Face type
{p}
Vertex figure
{q}
Symmetry Dual
Square tiling
(Quadrille)
{4,4} Tiling Regular 4-4 Square.svg {4} {4} *442
(p4m)
(self)
Triangular tiling
(Deltille)
{3,6} Tiling Regular 3-6 Triangular.svg {3} {6} *632
(p6m)
Hexagonal tiling
Hexagonal tiling
(Hextille)
{6,3} Tiling Regular 6-3 Hexagonal.svg {6} {3} *632
(p6m)
Triangular tiling

There is one degenerate regular tiling, {∞,2}, made from two apeirogons, each filling half the plane. This tiling is related to a 2-faced dihedron, {p,2}, on the sphere.

Euclidean star-tilings

There are no regular plane tilings of star polygons. There are many enumerations that fit in the plane (1/p + 1/q = 1/2), like {8/3,8}, {10/3,5}, {5/2,10}, {12/5,12}, etc, but none repeat periodically.

Hyperbolic tilings

Tessellations of hyperbolic 2-space can be called a hyperbolic tiling. There are infinitely many regular tilings in H2. As stated above, every positive integer pairs {p,q} such that 1/p + 1/q < 1/2 is a hyperbolic tiling.

There are 2 infinite forms of hyperbolic tilings whose faces or vertex figures are star polygons: {m/2, m} and their duals {m,m/2} with m=7,9,11,...

There are a number of different ways to display the hyperbolic plane, including the Poincaré disc model below which maps the plane into a circle, as shown below. It should be recognized that all of the polygon faces in the tilings below are equal-sized and only appear to get smaller near the edges due to the projection applied, very similar to the effect of a camera fisheye lens.

A sampling:

Poincaré disc projections with their Schläfli symbol
p \ q 3 4 5 6 7 8 9
3 (tetrahedron)
{3,3}
(octahedron)
{3,4}
(icosahedron)
{3,5}
(deltille) Uniform tiling 37-t0.png
{3,7}
Uniform tiling 38-t0.png
{3,8}
Uniform tiling 39-t0.png
{3,9}
4 (cube)
{4,3}
(quadrille)
{4,4}
Uniform tiling 45-t0.png
{4,5}
Uniform tiling 46-t0.png
{4,6}
Uniform tiling 47-t0.png
{4,7}
Uniform tiling 48-t0.png
{4,8}
{4,9}
5 (dodecahedron)
{5,3}
Uniform tiling 54-t0.png
{5,4}
Uniform tiling 55-t0.png
{5,5}
Uniform tiling 56-t0.png
{5,6}
Uniform tiling 57-t0.png
{5,7}
{5,8} {5,9}
6 (hextille)
{6,3}
Uniform tiling 64-t0.png
{6,4}
Uniform tiling 65-t0.png
{6,5}
Uniform tiling 66-t0.png
{6,6}
{6,7} {6,8} {6,9}
7 Uniform tiling 73-t0.png
{7,3}
Uniform tiling 74-t0.png
{7,4}
Uniform tiling 75-t0.png
{7,5}
{7,6} {7,7} {7,8} {7,9}
8 Uniform tiling 83-t0.png
{8,3}
Uniform tiling 84-t0.png
{8,4}
{8,5} {8,6} {8,7} {8,8} {8,9}
9 Uniform tiling 93-t0.png
{9,3}
{9,4} {9,5} {9,6} {9,7} {9,8} {9,9}

Four-dimensional regular polytopes

Regular polychora with Schläfli symbol {p,q,r} have cells of type {p,q}, faces of type {p}, edge figures {r}, and vertex figures {q,r}.

  • A vertex figure (of a polychoron) is a polyhedron, seen by the arrangement of neighboring vertices around a given vertex. For regular polychora, this vertex figure is a regular polyhedron.
  • An edge figure is a polygon, seen by the arrangement of faces around an edge. For regular polychora, this edge figure will always be a regular polygon.

The existence of a regular polychoron {p,q,r} is constrained by the existence of the regular polyhedra {p,q},{q,r}.

Each will exist in a space dependent upon this expression:

\sin \left ( \frac{\pi}{p} \right ) \sin \left(\frac{\pi}{r}\right) - \cos\left(\frac{\pi}{q}\right)
> 0 : Hyperspherical 3-space honeycomb or 4-space polychoron
= 0 : Euclidean 3-space honeycomb
< 0 : Hyperbolic 3-space honeycomb

These constraints allow for 21 forms: 6 are convex, 10 are nonconvex, one is a Euclidean 3-space honeycomb, and 4 are hyperbolic honeycombs.

The Euler characteristic χ for polychora is χ = V + FEC and is zero for all forms.

Convex

The 6 convex polychora are shown in the table below. All these polychora have a Euler characteristic (χ) of 0.

Name
Schläfli
{p,q,r}
Cells
{p,q}
Faces
{p}
Edges
{r}
Vertices
{q,r}
Dual
{r,q,p}
5-cell
(4-simplex)
(Pentachoron)
{3,3,3} 5
{3,3}
10
{3}
10
{3}
5
{3,3}
(self)
8-cell
(4-cube)
(Tesseract)
{4,3,3} 8
{4,3}
24
{4}
32
{3}
16
{3,3}
16-cell
16-cell
(4-orthoplex)
{3,3,4} 16
{3,3}
32
{3}
24
{4}
8
{3,4}
Tesseract
24-cell {3,4,3} 24
{3,4}
96
{3}
96
{3}
24
{4,3}
(self)
120-cell {5,3,3} 120
{5,3}
720
{5}
1200
{3}
600
{3,3}
600-cell
600-cell {3,3,5} 600
{3,3}
1200
{3}
720
{5}
120
{3,5}
120-cell
5-cell 8-cell 16-cell 24-cell 120-cell 600-cell
{3,3,3} {4,3,3} {3,3,4} {3,4,3} {5,3,3} {3,3,5}
Wireframe orthographic projections
Cell5-4dpolytope.png Hypercubestar.svg Cell16-4dpolytope.svg 24-cell graph ortho.png Cell120-4dpolytope.png Cell600-4dpolytope.svg
Solid orthographic projections (cell-centered)
Tetrahedron.png
tetrahedral
envelope
Hexahedron.png
cubic envelope
Octahedron.png
octahedral
envelope
Ortho solid 24-cell.png
cuboctahedral
envelope
Ortho solid 120-cell.png
truncated rhombic
triacontahedron
envelope
Ortho solid 600-cell.png
pentakis dodecahedral
envelope
Wireframe Schlegel diagrams (Perspective projection)
Schlegel wireframe 5-cell.png
(Cell-centered)
Schlegel wireframe 8-cell.png
(Cell-centered)
Schlegel wireframe 16-cell.png
(Cell-centered)
Schlegel wireframe 24-cell.png
(Cell-centered)
Schlegel wireframe 120-cell.png
(Cell-centered)
Schlegel wireframe 600-cell vertex-centered.png
(Vertex-centered)
Wireframe stereographic projections (Hyperspherical)
Stereographic polytope 5cell.png Stereographic polytope 8cell.png Stereographic polytope 16cell.png Stereographic polytope 24cell.png Stereographic polytope 120cell.png Stereographic polytope 600cell.png

Degenerate (Spherical)

Ditopes and hosotopes exist as regular tessellations of the 3-sphere.

Regular ditopes (2 facets) include: {3,3,2}, {3,4,2}, {4,3,2}, {5,3,2}, {3,5,2}, {p,2,2}, and their hosotope duals (2 vertices): {2,3,3}, {2,4,3}, {2,3,4}, {2,3,5}, {2,5,3}.

Non-convex

There are ten regular star polychora, which can be called Schläfli-Hess polychora and their vertices are based on the convex 120-cell {5,3,3} and 600-cell {3,3,5}:

Ludwig Schläfli found four of them and skipped the last six because he would not allow forms that failed the Euler characteristic on cells or vertex figures (For zero-hole toruses: F+V-E=2). Edmund Hess (1843-1903) completed the full list of ten in his 1883 German book Einleitung in die Lehre von der Kugelteilung mit besonderer Berücksichtigung ihrer Anwendung auf die Theorie der Gleichflächigen und der gleicheckigen Polyeder[1].

There are 4 unique edge arrangements and 7 unique face arrangements from these 10 nonconvex polychora, shown as orthogonal projections:

Name
Wireframe Solid Schläfli
{p, q,r}
Coxeter-Dynkin
Cells
{p, q}
Faces
{p}
Edges
{r}
Vertices
{q, r}
Density χ Symmetry group Dual
{r, q,p}
Icosahedral 120-cell Schläfli-Hess polychoron-wireframe-3.png Ortho solid 007-uniform polychoron 35p-t0.png {3,5,5/2}
CD ring.pngCD 3.pngCD dot.pngCD 5.pngCD dot.pngCD 5-2.pngCD dot.png
120
{3,5}
Icosahedron.png
1200
{3}
Triangle.Equilateral.svg
720
{5/2}
Pentagram.svg
120
{5,5/2}
Great dodecahedron.png
4 480 H4 Small stellated 120-cell
Small stellated 120-cell Schläfli-Hess polychoron-wireframe-2.png Ortho solid 010-uniform polychoron p53-t0.png {5/2,5,3}
CD dot.pngCD 3.pngCD dot.pngCD 5.pngCD dot.pngCD 5-2.pngCD ring.png
120
{5/2,5}
Small stellated dodecahedron.png
720
{5/2}
Pentagram.svg
1200
{3}
Triangle.Equilateral.svg
120
{5,3}
Dodecahedron.png
4 -480 H4 Icosahedral 120-cell
Great 120-cell Schläfli-Hess polychoron-wireframe-3.png Ortho solid 008-uniform polychoron 5p5-t0.png {5,5/2,5}
CD ring.pngCD 5.pngCD dot.pngCD 5-2.pngCD dot.pngCD 5.pngCD dot.png
120
{5,5/2}
Great dodecahedron.png
720
{5}
Pentagon.svg
720
{5}
Pentagon.svg
120
{5/2,5}
Small stellated dodecahedron.png
6 0 H4 Self-dual
Grand 120-cell Schläfli-Hess polychoron-wireframe-3.png Ortho solid 009-uniform polychoron 53p-t0.png {5,3,5/2}
CD ring.pngCD 5.pngCD dot.pngCD 3.pngCD dot.pngCD 5-2.pngCD dot.png
120
{5,3}
Dodecahedron.png
720
{5}
Pentagon.svg
720
{5/2}
Pentagram.svg
120
{3,5/2}
Great icosahedron.png
20 0 H4 Great stellated 120-cell
Great stellated 120-cell Schläfli-Hess polychoron-wireframe-4.png Ortho solid 012-uniform polychoron p35-t0.png {5/2,3,5}
CD dot.pngCD 5.pngCD dot.pngCD 3.pngCD dot.pngCD 5-2.pngCD ring.png
120
{5/2,3}
Great stellated dodecahedron.png
720
{5/2}
Pentagram.svg
720
{5}
Pentagon.svg
120
{3,5}
Icosahedron.png
20 0 H4 Grand 120-cell
Grand stellated 120-cell Schläfli-Hess polychoron-wireframe-4.png Ortho solid 013-uniform polychoron p5p-t0.png {5/2,5,5/2}
CD ring.pngCD 5-2.pngCD dot.pngCD 5.pngCD dot.pngCD 5-2.pngCD dot.png
120
{5/2,5}
Small stellated dodecahedron.png
720
{5/2}
Pentagram.svg
720
{5/2}
Pentagram.svg
120
{5,5/2}
Great dodecahedron.png
66 0 H4 Self-dual
Great grand 120-cell Schläfli-Hess polychoron-wireframe-2.png Ortho solid 011-uniform polychoron 53p-t0.png {5,5/2,3}
CD ring.pngCD 5.pngCD dot.pngCD 5-2.pngCD dot.pngCD 3.pngCD dot.png
120
{5,5/2}
Great dodecahedron.png
720
{5}
Pentagon.svg
1200
{3}
Triangle.Equilateral.svg
120
{5/2,3}
Great stellated dodecahedron.png
76 -480 H4 Great icosahedral 120-cell
Great icosahedral 120-cell Schläfli-Hess polychoron-wireframe-4.png Ortho solid 014-uniform polychoron 3p5-t0.png {3,5/2,5}
CD dot.pngCD 5.pngCD dot.pngCD 5-2.pngCD dot.pngCD 3.pngCD ring.png
120
{3,5/2}
Great icosahedron.png
1200
{3}
Triangle.Equilateral.svg
720
{5}
Pentagon.svg
120
{5/2,5}
Small stellated dodecahedron.png
76 480 H4 Great grand 120-cell
Grand 600-cell Schläfli-Hess polychoron-wireframe-4.png Ortho solid 015-uniform polychoron 33p-t0.png {3,3,5/2}
CD ring.pngCD 3.pngCD dot.pngCD 3.pngCD dot.pngCD 5-2.pngCD dot.png
600
{3,3}
Tetrahedron.png
1200
{3}
Triangle.Equilateral.svg
720
{5/2}
Pentagram.svg
120
{3,5/2}
Great icosahedron.png
191 0 H4 Great grand stellated 120-cell
Great grand stellated 120-cell Schläfli-Hess polychoron-wireframe-1.png Ortho solid 016-uniform polychoron p33-t0.png {5/2,3,3}
CD dot.pngCD 3.pngCD dot.pngCD 3.pngCD dot.pngCD 5-2.pngCD ring.png
120
{5/2,3}
Great stellated dodecahedron.png
720
{5/2}
Pentagram.svg
1200
{3}
Triangle.Equilateral.svg
600
{3,3}
Tetrahedron.png
191 0 H4 Grand 600-cell

There are 4 failed potential nonconvex regular polychora permutations: {3,5/2,3}, {4,3,5/2}, {5/2,3,4}, {5/2,3,5/2}. Their cells and vertex figures exist, but they do not cover a hypersphere with a finite number of repetitions.

Tessellations of Euclidean 3-space

Perspective view within wireframe cubic honeycomb{4,3,4}

There is only one regular tessellation of 3-space (honeycombs):

Name Schläfli
symbol

{p,q,r}
Cell
type
{p,q}
Face
type
{p}
Edge
figure
{r}
Vertex
figure

{q,r}
χ Dual
Cubic honeycomb {4,3,4} {4,3} {4} {4} {3,4} 0 Self-dual

Tessellations of hyperbolic 3-space

Tessellations of hyperbolic 3-space can be called hyperbolic honeycombs. There are 4 regular honeycombs in H3:

Name Schläfli
Symbol
{p,q,r}
Cell
type
{p,q}
Face
type
{p}
Edge
figure
{r}
Vertex
figure

{q,r}
χ Dual
Order-3 icosahedral honeycomb {3,5,3} {3,5} {3} {3} {5,3} 0 Self-dual
Order-5 cubic honeycomb {4,3,5} {4,3} {4} {5} {3,5} 0 {5,3,4}
Order-4 dodecahedral honeycomb {5,3,4} {5,3} {5} {4} {3,4} 0 {4,3,5}
Order-5 dodecahedral honeycomb {5,3,5} {5,3} {5} {5} {3,5} 0 Self-dual

Here are some projected images: The first shows the perspective from the center of the disc in a Beltrami-Klein model, and the second and third from the outside with a Poincaré disk model.

Hyperbolic orthogonal dodecahedral honeycomb.png
{5,3,4}
(8 dodecahedra at a vertex)
Hyperb gcubic hc.png
{4,3,5}
(20 cubes at a vertex)
Hyperb icosahedral hc.png
{3,5,3}
(12 icosahedra at a vertex)

There are also 11 H3 honeycombs which have infinite (Euclidean) cells and/or vertex figures: {3,3,6}, {6,3,3}, {3,4,4}, {4,4,3}, {3,6,3}, {4,3,6}, {6,3,4}, {4,4,4}, {5,3,6}, {6,3,5}, {6,3,6}.

Five-dimensional regular polytopes and higher

In five dimensions, a regular polytope can be named as {p,q,r,s} where {p,q,r} is the hypercell (or teron) type, {p,q} is the cell type, {p} is the face type, and {s} is the face figure, {r,s} is the edge figure, and {q,r,s} is the vertex figure.

A 5-polytope has been called a polyteron, and if infinite (i.e. a honeycomb).

A vertex figure (of a 5-polytope) is a polychoron, seen by the arrangement of neighboring vertices to each vertex.
An edge figure (of a 5-polytope) is a polyhedron, seen by the arrangement of faces around each edge.
A face figure (of a 5-polytope) is a polygon, seen by the arrangement of cells around each face.

A regular polytope {p,q,r,s} exists only if {p,q,r} and {q,r,s} are regular polychora.

The space it fits in is based on the expression:

\frac{\cos^2\left(\frac{\pi}{q}\right)}{\sin^2\left(\frac{\pi}{p}\right)} + \frac{\cos^2\left(\frac{\pi}{r}\right)}{\sin^2\left(\frac{\pi}{s}\right)}
< 1 : Spherical 4-space tessellation or 5-space polytope
= 1 : Euclidean 4-space tessellation
> 1 : hyperbolic 4-space tessellation

Enumeration of these constraints produce 3 convex polytopes, zero nonconvex polytopes, 3 4-space tessellations, and 5 hyperbolic 4-space tessellations. There are no non-convex regular polytopes in five dimensions or higher.

Convex

In dimensions 5 and higher, there are only three kinds of convex regular polytopes. [Coxeter, Regular Polytopes, Table I: Regular polytopes, (iii) The three regular polytopes in n dimensions (n>=5), pp. 294-295]

Name Schläfli
Symbol
{p1,p2,...,pn-1}
Facet
type
Vertex
figure
Dual
n-simplex {3,3,3,...,3} {3,3,...,3} {3,3,...,3} Self-dual
n-cube {4,3,3,...,3} {4,3,...,3} {3,3,...,3} n-orthoplex
n-orthoplex {3,...,3,3,4} {3,...,3,3} {3,...,3,4} n-cube

5-dimensions

Name Schläfli
Symbol
{p,q,r,s}
Facets
{p,q,r}
Cells
{p,q}
Faces
{p}
Edges Vertices Face
figure
{s}
Edge
figure
{r,s}
Vertex
figure

{q,r,s}
5-simplex {3,3,3,3} 6
{3,3,3}
15
{3,3}
20
{3}
15 6 {3} {3,3} {3,3,3}
5-cube {4,3,3,3} 10
{4,3,3}
40
{4,3}
80
{4}
80 32 {3} {3,3} {3,3,3}
5-orthoplex {3,3,3,4} 32
{3,3,3}
80
{3,3}
80
{3}
40 10 {4} {3,4} {3,3,4}
Complete graph K6.svg
5-simplex
Penteract ortho petrie.svg
5-cube
Cross graph 5.svg
5-orthoplex

6-dimensions

Name Schläfli
symbol
Vertices Edges Faces Cells 4-faces 5-faces χ
6-simplex {3,3,3,3,3} 7 21 35 35 21 7 0
6-cube {4,3,3,3,3} 64 192 240 160 60 12 0
6-orthoplex {3,3,3,3,4} 12 60 160 240 192 64 0
Complete graph K7.svg
6-simplex
Hexeract ortho petrie.svg
6-cube
Cross graph 6.svg
6-orthoplex

7-dimensions

Name Schläfli
symbol
Vertices Edges Faces Cells 4-faces 5-faces 6-faces χ
7-simplex {3,3,3,3,3,3} 8 28 56 70 56 28 8 2
7-cube {4,3,3,3,3,3} 128 448 672 560 280 84 14 2
7-orthoplex {3,3,3,3,3,4} 14 84 280 560 672 448 128 2
Complete graph K8.svg
7-simplex
Hepteract ortho petrie.svg
7-cube
Cross graph 7.svg
7-orthoplex

8-dimensions

Name Schläfli
symbol
Vertices Edges Faces Cells 4-faces 5-faces 6-faces 7-faces χ
8-simplex {3,3,3,3,3,3,3} 9 36 84 126 126 84 36 9 0
8-cube {4,3,3,3,3,3,3} 256 1024 1792 1792 1120 448 112 16 0
8-orthoplex {3,3,3,3,3,3,4} 16 112 448 1120 1792 1792 1024 256 0
Complete graph K9.svg
8-simplex
Octeract Petrie polygon.svg
8-cube
Cross graph 8.svg
8-orthoplex

9-dimensions

Name Schläfli
symbol
Vertices Edges Faces Cells 4-faces 5-faces 6-faces 7-faces 8-faces χ
9-simplex {38} 10 45 120 210 252 210 120 45 10 2
9-cube {4,37} 512 2304 4608 5376 4032 2016 672 144 18 2
9-orthoplex {37,4} 18 144 672 2016 4032 5376 4608 2304 512 2
Complete graph K9.svg
9-simplex
Enneract ortho petrie.svg
9-cube
Cross graph 8.svg
9-orthoplex

10-dimensions

Name Schläfli
symbol
Vertices Edges Faces Cells 4-faces 5-faces 6-faces 7-faces 8-faces 9-faces χ
10-simplex {38} 11 55 165 330 462 462 330 165 55 11 0
10-cube {4,38} 1024 5120 11520 15360 13440 8064 3360 960 180 20 0
10-orthoplex {38,4} 20 180 960 3360 8064 13440 15360 11520 5120 1024 0
Complete graph K10.svg
10-simplex
10cube ortho polygon.svg
10-cube
Cross graph 9.svg
10-orthoplex

...

Nonconvex

There are no non-convex regular polytopes in five dimensions or higher.

Tessellations of Euclidean 4-space

There are three kinds of infinite regular tessellations (honeycombs) that can tessellate four dimensional space:

Name Schläfli
Symbol
{p,q,r,s}
Facet
type
{p,q,r}
Cell
type
{p,q}
Face
type
{p}
Face
figure
{s}
Edge
figure
{r,s}
Vertex
figure

{q,r,s}
Dual
Tesseractic honeycomb {4,3,3,4} {4,3,3} {4,3} {4} {4} {3,4} {3,3,4} Self-dual
Hexadecachoric honeycomb {3,3,4,3} {3,3,4} {3,3} {3} {3} {4,3} {3,4,3} {3,4,3,3}
Icositetrachoric honeycomb {3,4,3,3} {3,4,3} {3,4} {3} {3} {3,3} {4,3,3} {3,3,4,3}
Tesseractic tetracomb.png
Projected portion of {4,3,3,4}
(Tesseractic honeycomb)
Demitesseractic tetra hc.png
Projected portion of {3,3,4,3}
(Hexadecachoronic honeycomb)
Icositetrachoronic tetracomb.png
Projected portion of {3,4,3,3}
(Icositetrachoronic honeycomb)

The hypercube honeycomb is the only family of regular honeycombs that can tessellate each dimension, five or higher, formed by hypercube facets, four around every ridge.

Name Schläfli
{p1, p2, ..., pn−1}
Facet
type
Vertex
figure
Dual
Square tiling {4,4} {4} {4} Self-dual
Cubic honeycomb {4,3,4} {4,3} {3,4} Self-dual
Tesseractic honeycomb {4,32,4} {4,32} {32,4} Self-dual
Penteractic honeycomb {4,33,4} {4,33} {33,4} Self-dual
Hexeractic honeycomb {4,34,4} {4,34} {34,4} Self-dual
Hepteractic honeycomb {4,35,4} {4,35} {35,4} Self-dual
Octeractic honeycomb {4,36,4} {4,36} {36,4} Self-dual
n-hypercube honeycomb {4,3n-2,4} {4,3n-2} {3n-2,4} Self-dual

Tessellations of hyperbolic 4-space

There are five kinds of convex regular honeycombs and four kinds of star-honeycombs in H4 space. [Coxeter, The Beauty of Geometry: Twelve Essays, Chapter 10: Regular honeycombs in hyperbolic space, Summary tables IV p213]

Five convex regular honeycombs in H4:

Name Schläfli
Symbol
{p,q,r,s}
Facet
type
{p,q,r}
Cell
type
{p,q}
Face
type
{p}
Face
figure
{s}
Edge
figure
{r,s}
Vertex
figure

{q,r,s}
Dual
Order-5 pentachoric honeycomb {3,3,3,5} {3,3,3} {3,3} {3} {5} {3,5} {3,3,5} {5,3,3,3}
Order-3 hecatonicosachoric honeycomb {5,3,3,3} {5,3,3} {5,3} {5} {3} {3,3} {3,3,3} {3,3,3,5}
Order-5 tesseractic honeycomb {4,3,3,5} {4,3,3} {4,3} {4} {5} {3,5} {3,3,5} {5,3,3,4}
Order-4 hecatonicosachoric honeycomb {5,3,3,4} {5,3,3} {5,3} {5} {4} {3,4} {3,3,4} {4,3,3,5}
Order-5 hecatonicosachoric honeycomb {5,3,3,5} {5,3,3} {5,3} {5} {5} {3,5} {3,3,5} Self-dual

There are four regular star-honeycombs in H4 space:

Name Schläfli
Symbol
{p,q,r,s}
Facet
type
{p,q,r}
Cell
type
{p,q}
Face
type
{p}
Face
figure
{s}
Edge
figure
{r,s}
Vertex
figure

{q,r,s}
Dual
Order-3 small stellated hecatonicosachoric honeycomb {5/2,5,3,3} {5/2,5,3} {5/2,5} {5} {5} {3,3} {5,3,3} {3,3,5,5/2}
Pentagrammic-order hexacosichoric honeycomb {3,3,5,5/2} {3,3,5} {3,3} {3} {5/2} {5,5/2} {3,5,5/2} {5/2,5,3,3}
Order-5 icosahedral hecatonicosachoric honeycomb {3,5,5/2,5} {3,5,5/2} {3,5} {3} {5} {5/2,5} {5,5/2,5} {5,5/2,5,3}
Order-3 great hecatonicosachoric honeycomb {5,5/2,5,3} {5,5/2,5} {5,5/2} {5} {3} {5,3} {5/2,5,3} {3,5,5/2,5}

There are also 2 H4 honeycombs with infinite (Euclidean) facets or vertex figures: {3,4,3,4}, {4,3,4,3}

There are no finite-faceted regular tessellations of hyperbolic space of dimension 5 or higher.

There are 5 regular honeycombs in H5 with infinite (Euclidean) facets or vertex figures: {3,4,3,3,3},{3,3,4,3,3},{3,3,3,4,3},{3,4,3,3,4},{4,3,3,4,3}.

Even allowing for infinite (Euclidean) facets and/or vertex figures, there are no regular tessellations of hyperbolic space of dimension 6 or higher.

Apeirotopes

An apeirotope is, like any other polytope, an unbounded hyper-surface. The difference is that whereas a polytope's hyper-surface curls back on itself to close round a finite volume of hyperspace, an apeirotope does not curl back.

Some people regard apeirotopes as just a special kind of polytope, while others regard them as rather different things.

Two dimensions

A regular apeirogon is a regular division of an infinitely long line into equal segments, joined by vertices. It has regular embeddings in the plane, and in higher-dimensional spaces. In two dimensions it can form a straight line or a zig-zag. In three dimensions, it traces out a helical spiral. The zig-zag and spiral forms are said to be skew.

Three dimensions

An apeirohedron is an infinite polyhedral surface. Like an apeirogon, it can be flat or skew. A flat apeirohedron is just a tiling of the plane. A skew apeirohedron is an intricate honeycomb-like structure which divides space into two regions.

There are thirty regular apeirohedra in Euclidean space. See section 7E of Abstract Regular Polytopes, by McMullen and Schulte. These include the tessellations of type {4,4},{6,3} and {3,6} above, as well as (in the plane) polytopes of type: \{\infty,3\}, \{\infty,4\} and \{\infty,6\}, and in 3-dimensional space, blends of these with either an apeirogon or a line segment, and the "pure" 3-dimensional apeirohedra (12 in number)

Four and higher dimensions

The apeirochora have not been completely classified as of 2006.

Abstract polytopes

The abstract polytopes arose out of an attempt to study polytopes apart from the geometrical space they are embedded in. They include the tessellations of spherical, euclidean and hyperbolic space, tessellations of other manifolds, and many other objects that do not have a well-defined topology, but instead may be characterised by their "local" topology. There are infinitely many in every dimension. See this atlas for a sample. Some notable examples of abstract polytopes that do not appear elsewhere in this list are the 11-cell and the 57-cell.

See also

References

  • Coxeter, Regular Polytopes, 3rd. ed., Dover Publications, 1973. ISBN 0-486-61480-8. (Tables I and II: Regular polytopes and honeycombs, pp. 294-296)
  • Coxeter, The Beauty of Geometry: Twelve Essays, Dover Publications, 1999 ISBN 0-486-40919-8 (Chapter 10: Regular honeycombs in hyperbolic space, Summary tables II,III,IV,V, p212-213)
  • D. M. Y. Sommerville, An Introduction to the Geometry of n Dimensions. New York, E. P. Dutton, 1930. 196 pp. (Dover Publications edition, 1958) Chapter X: The Regular Polytopes

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