- Order-5 dodecahedral honeycomb
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Order-5 dodecahedral honeycomb (No image) Type Hyperbolic regular honeycomb Schläfli symbol {5,3,5} Coxeter-Dynkin diagram Cells dodecahedron {5,3} Faces pentagon {5} Edge figure pentagon {5} Vertex figure
{3,5}Cells/edge {5,3}5 Cells/vertex {5,3}20 Euler characteristic 0 Dual Self-dual Coxeter group K3, [5,3,5] Properties Regular The order-5 dodecahedral honeycomb is one of four regular space-filling tessellations (or honeycombs) in hyperbolic 3-space.
Five dodecahedra exist on each edge, and 20 dodecahedra around each vertex.
The dihedral angle of a dodecahedron is ~116.6°, so no more than three of them can fit around an edge in Euclidean 3-space. In curved space, however, the dihedral angle depends on the size of the figure; a hyperbolic regular dodecahedron can be made with dihedral angles as small as one-sixth of a circle (if its vertices are at infinity).
Related honeycombs
There is another honeycomb in hyperbolic 3-space called the order-4 dodecahedral honeycomb which has only 4 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 3 dodecahedra on each edge.
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.
See also
- Convex uniform honeycombs in hyperbolic space
- List of regular polytopes
- 57-cell - An abstract regular polychoron which shared the {5,3,5} symbol.
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)
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