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Uniform honeycombs in hyperbolic space


In hyperbolic geometry, a uniform honeycomb in hyperbolic space is a uniform tessellation of uniform polyhedral cells. In 3-dimensional hyperbolic space there are nine Coxeter group families of compact convex uniform honeycombs, generated as Wythoff constructions, and represented by permutations of rings of the Coxeter diagrams for each family.

Honeycombs are divided between compact and paracompact forms defined by Coxeter groups, the first category only including finite cells and vertex figures (finite subgroups), and the second includes affine subgroups.

The nine compact Coxeter groups are listed here with their Coxeter diagrams, in order of the relative volumes of their fundamental simplex domains.

These 9 families generate a total of 76 unique uniform honeycombs. The full list of hyperbolic uniform honeycombs has not been proven and an unknown number of non-Wythoffian forms exist. One known example is cited with the {3,5,3} family below. Only two families are related as a mirror-removal halving: [5,31,1] ↔ [5,3,4,1+].

There are just two radical subgroups with nonsimplectic domains that can be generated by removing a set of two or more mirrors separated by all other mirrors by even-order branches. One is [(4,3,4,3*)], represented by Coxeter diagrams CDel branch c1-2.pngCDel 4a4b.pngCDel branch.pngCDel labels.png an index 6 subgroup with a trigonal trapezohedron fundamental domainCDel node c1.pngCDel splitplit1u.pngCDel branch3u c2.pngCDel 3a3buc-cross.pngCDel branch3u c1.pngCDel splitplit2u.pngCDel node c2.png, which can be extended by restoring one mirror as CDel branchu c1-2.pngCDel 3ab.pngCDel branch c2-1.pngCDel split2-44.pngCDel node.png. The other is [4,(3,5)*], index 120 with a dodecahedral fundamental domain.


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