Order-5 dodecahedral honeycomb
Regular tiling of hyperbolic 3-space
In hyperbolic geometry , the order-5 dodecahedral honeycomb is one of four compact regular space-filling tessellations (or honeycombs ) in hyperbolic 3-space . With Schläfli symbol {5,3,5}, it has five dodecahedral cells around each edge , and each vertex is surrounded by twenty dodecahedra. Its vertex figure is an icosahedron .
A geometric honeycomb is a space-filling of polyhedral or higher-dimensional cells , so that there are no gaps. It is an example of the more general mathematical tiling or tessellation in any number of dimensions.
Honeycombs are usually constructed in ordinary Euclidean ("flat") space, like the convex uniform honeycombs . They may also be constructed in non-Euclidean spaces , such as hyperbolic uniform honeycombs . Any finite uniform polytope can be projected to its circumsphere to form a uniform honeycomb in spherical space.
Description
The dihedral angle of a Euclidean regular dodecahedron is ~116.6°, so no more than three of them can fit around an edge in Euclidean 3-space. In hyperbolic space, however, the dihedral angle is smaller than it is in Euclidean space, and depends on the size of the figure; the smallest possible dihedral angle is 60°, for an ideal hyperbolic regular dodecahedron with infinitely long edges. The dodecahedra in this dodecahedral honeycomb are sized so that all of their dihedral angles are exactly 72°.
Images
It is analogous to the 2D hyperbolic order-5 pentagonal tiling , {5,5}
There are four regular compact honeycombs in 3D hyperbolic space:
There is another honeycomb in hyperbolic 3-space called the order-4 dodecahedral honeycomb , {5,3,4}, which has only four dodecahedra per edge. These honeycombs are also related to the 120-cell which can be considered as a honeycomb in positively curved space (the surface of a 4-dimensional sphere), with three dodecahedra on each edge, {5,3,3}. Lastly the dodecahedral ditope , {5,3,2} exists on a 3-sphere , with 2 hemispherical cells.
There are nine uniform honeycombs in the [5,3,5] Coxeter group family, including this regular form. Also the bitruncated form, t1,2 {5,3,5}, , of this honeycomb has all truncated icosahedron cells.
[5,3,5] family honeycombs
{5,3,5}
r{5,3,5}
t{5,3,5}
rr{5,3,5}
t0,3 {5,3,5}
2t{5,3,5}
tr{5,3,5}
t0,1,3 {5,3,5}
t0,1,2,3 {5,3,5}
The Seifert–Weber space is a compact manifold that can be formed as a quotient space of the order-5 dodecahedral honeycomb.
This honeycomb is a part of a sequence of polychora and honeycombs with icosahedron vertex figures:
{p,3,5} polytopes
Space
S3
H3
Form
Finite
Compact
Paracompact
Noncompact
Name
{3,3,5}
{4,3,5}
{5,3,5}
{6,3,5}
{7,3,5}
{8,3,5}
... {∞,3,5}
Image
Cells
{3,3}
{4,3}
{5,3}
{6,3}
{7,3}
{8,3}
{∞,3}
This honeycomb is a part of a sequence of regular polytopes and honeycombs with dodecahedral cells:
{5,3,p} polytopes
Space
S3
H3
Form
Finite
Compact
Paracompact
Noncompact
Name
{5,3,3}
{5,3,4}
{5,3,5}
{5,3,6}
{5,3,7}
{5,3,8}
... {5,3,∞}
Image
Vertex figure
{3,3}
{3,4}
{3,5}
{3,6}
{3,7}
{3,8}
{3,∞}
{p,3,p} regular honeycombs
Space
S3
Euclidean E3
H3
Form
Finite
Affine
Compact
Paracompact
Noncompact
Name
{3,3,3}
{4,3,4}
{5,3,5}
{6,3,6}
{7,3,7}
{8,3,8}
...{∞,3,∞}
Image
Cells
{3,3}
{4,3}
{5,3}
{6,3}
{7,3}
{8,3}
{∞,3}
Vertex figure
{3,3}
{3,4}
{3,5}
{3,6}
{3,7}
{3,8}
{3,∞}
Rectified order-5 dodecahedral honeycomb
Rectified order-5 dodecahedral honeycomb
Type
Uniform honeycombs in hyperbolic space
Schläfli symbol
r{5,3,5} t1 {5,3,5}
Coxeter diagram
Cells
r{5,3} {3,5}
Faces
triangle {3}pentagon {5}
Vertex figure
pentagonal prism
Coxeter group
K
¯ ¯ -->
3
{\displaystyle {\overline {K}}_{3}}
, [5,3,5]
Properties
Vertex-transitive, edge-transitive
The rectified order-5 dodecahedral honeycomb , , has alternating icosahedron and icosidodecahedron cells, with a pentagonal prism vertex figure .
It can be seen as analogous to the 2D hyperbolic order-4 pentagonal tiling , r{5,5}
There are four rectified compact regular honeycombs:
r{p,3,5}
Space
S3
H3
Form
Finite
Compact
Paracompact
Noncompact
Name
r{3,3,5}
r{4,3,5}
r{5,3,5}
r{6,3,5}
r{7,3,5}
... r{∞,3,5}
Image
Cells{3,5}
r{3,3}
r{4,3}
r{5,3}
r{6,3}
r{7,3}
r{∞,3}
Truncated order-5 dodecahedral honeycomb
Truncated order-5 dodecahedral honeycomb
Type
Uniform honeycombs in hyperbolic space
Schläfli symbol
t{5,3,5} t0,1 {5,3,5}
Coxeter diagram
Cells
t{5,3} {3,5}
Faces
triangle {3}
decagon {10}
Vertex figure
pentagonal pyramid
Coxeter group
K
¯ ¯ -->
3
{\displaystyle {\overline {K}}_{3}}
, [5,3,5]
Properties
Vertex-transitive
The truncated order-5 dodecahedral honeycomb , , has icosahedron and truncated dodecahedron cells, with a pentagonal pyramid vertex figure .
Bitruncated order-5 dodecahedral honeycomb
Bitruncated order-5 dodecahedral honeycomb
Type
Uniform honeycombs in hyperbolic space
Schläfli symbol
2t{5,3,5} t1,2 {5,3,5}
Coxeter diagram
Cells
t{3,5}
Faces
pentagon {5}hexagon {6}
Vertex figure
tetragonal disphenoid
Coxeter group
2
× × -->
K
¯ ¯ -->
3
{\displaystyle 2\times {\overline {K}}_{3}}
, [[5,3,5]]
Properties
Vertex-transitive, edge-transitive, cell-transitive
The bitruncated order-5 dodecahedral honeycomb , , has truncated icosahedron cells, with a tetragonal disphenoid vertex figure .
Cantellated order-5 dodecahedral honeycomb
Cantellated order-5 dodecahedral honeycomb
Type
Uniform honeycombs in hyperbolic space
Schläfli symbol
rr{5,3,5} t0,2 {5,3,5}
Coxeter diagram
Cells
rr{5,3} r{3,5} {}x{5}
Faces
triangle {3}square {4}pentagon {5}
Vertex figure
wedge
Coxeter group
K
¯ ¯ -->
3
{\displaystyle {\overline {K}}_{3}}
, [5,3,5]
Properties
Vertex-transitive
The cantellated order-5 dodecahedral honeycomb , , has rhombicosidodecahedron , icosidodecahedron , and pentagonal prism cells, with a wedge vertex figure .
Cantitruncated order-5 dodecahedral honeycomb
Cantitruncated order-5 dodecahedral honeycomb
Type
Uniform honeycombs in hyperbolic space
Schläfli symbol
tr{5,3,5} t0,1,2 {5,3,5}
Coxeter diagram
Cells
tr{5,3} t{3,5} {}x{5}
Faces
square {4}pentagon {5}hexagon {6}decagon {10}
Vertex figure
mirrored sphenoid
Coxeter group
K
¯ ¯ -->
3
{\displaystyle {\overline {K}}_{3}}
, [5,3,5]
Properties
Vertex-transitive
The cantitruncated order-5 dodecahedral honeycomb , , has truncated icosidodecahedron , truncated icosahedron , and pentagonal prism cells, with a mirrored sphenoid vertex figure .
Runcinated order-5 dodecahedral honeycomb
The runcinated order-5 dodecahedral honeycomb , , has dodecahedron and pentagonal prism cells, with a triangular antiprism vertex figure .
Runcitruncated order-5 dodecahedral honeycomb
The runcitruncated order-5 dodecahedral honeycomb , , has truncated dodecahedron , rhombicosidodecahedron , pentagonal prism , and decagonal prism cells, with an isosceles-trapezoidal pyramid vertex figure .
The runcicantellated order-5 dodecahedral honeycomb is equivalent to the runcitruncated order-5 dodecahedral honeycomb.
Four runcitruncated regular compact honeycombs in H3
Image
Symbols
t0,1,3 {5,3,4}
t0,1,3 {4,3,5}
t0,1,3 {3,5,3}
t0,1,3 {5,3,5}
Vertex figure
Omnitruncated order-5 dodecahedral honeycomb
The omnitruncated order-5 dodecahedral honeycomb , , has truncated icosidodecahedron and decagonal prism cells, with a phyllic disphenoid vertex figure .
Three omnitruncated regular compact honeycombs in H3
Image
Symbols
t0,1,2,3 {4,3,5}
t0,1,2,3 {3,5,3}
t0,1,2,3 {5,3,5}
Vertex figure
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)
Norman Johnson Uniform Polytopes , Manuscript
N.W. Johnson : The Theory of Uniform Polytopes and Honeycombs , Ph.D. Dissertation, University of Toronto, 1966
N.W. Johnson: Geometries and Transformations , (2018) Chapter 13: Hyperbolic Coxeter groups