| Order-7 tetrahedral honeycomb | |
|---|---|
| Type | Hyperbolic regular honeycomb | 
| Schläfli symbols | {3,3,7} | 
| Coxeter diagrams |        | 
| Cells | {3,3}  | 
| Faces | {3} | 
| Edge figure | {7} | 
| Vertex figure | {3,7}  | 
| Dual | {7,3,3} | 
| Coxeter group | [7,3,3] | 
| Properties | Regular | 
In the geometry of hyperbolic 3-space, the order-7 tetrahedral honeycomb is a regular space-filling tessellation (or honeycomb) with Schläfli symbol {3,3,7}. It has seven tetrahedra {3,3} around each edge. All vertices are ultra-ideal (existing beyond the ideal boundary) with infinitely many tetrahedra existing around each vertex in an order-7 triangular tiling vertex arrangement.
Images
|  Poincaré disk model (cell-centered) |  Rendered intersection of honeycomb with the ideal plane in Poincaré half-space model | 
Related polytopes and honeycombs
It is a part of a sequence of regular polychora and honeycombs with tetrahedral cells, {3,3,p}.
| {3,3,p} polytopes | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Space | S3 | H3 | |||||||||
| Form | Finite | Paracompact | Noncompact | ||||||||
| Name | {3,3,3}        | {3,3,4}             | {3,3,5}        | {3,3,6}             | {3,3,7}        | {3,3,8}              | ... {3,3,∞}              | ||||
| Image |  |  |  |  |  |  |  | ||||
| Vertex figure |  {3,3}      |  {3,4}         |  {3,5}      |  {3,6}         |  {3,7}      |  {3,8}          |  {3,∞}          | ||||
It is a part of a sequence of hyperbolic honeycombs with order-7 triangular tiling vertex figures, {p,3,7}.
| {3,3,7} | {4,3,7} | {5,3,7} | {6,3,7} | {7,3,7} | {8,3,7} | {∞,3,7} | 
|---|---|---|---|---|---|---|
|  |  |  |  |  |  |  | 
It is a part of a sequence of hyperbolic honeycombs, {3,p,7}.
Order-8 tetrahedral honeycomb
| Order-8 tetrahedral honeycomb | |
|---|---|
| Type | Hyperbolic regular honeycomb | 
| Schläfli symbols | {3,3,8} {3,(3,4,3)} | 
| Coxeter diagrams |               =       | 
| Cells | {3,3}  | 
| Faces | {3} | 
| Edge figure | {8} | 
| Vertex figure | {3,8}  {(3,4,3)}  | 
| Dual | {8,3,3} | 
| Coxeter group | [3,3,8] [3,((3,4,3))] | 
| Properties | Regular | 
In the geometry of hyperbolic 3-space, the order-8 tetrahedral honeycomb is a regular space-filling tessellation (or honeycomb) with Schläfli symbol {3,3,8}. It has eight tetrahedra {3,3} around each edge. All vertices are ultra-ideal (existing beyond the ideal boundary) with infinitely many tetrahedra existing around each vertex in an order-8 triangular tiling vertex arrangement.
|  Poincaré disk model (cell-centered) |  Rendered intersection of honeycomb with the ideal plane in Poincaré half-space model | 
It has a second construction as a uniform honeycomb, Schläfli symbol {3,(3,4,3)}, Coxeter diagram, 




 , with alternating types or colors of tetrahedral cells. In Coxeter notation the half symmetry is [3,3,8,1+] = [3,((3,4,3))].
, with alternating types or colors of tetrahedral cells. In Coxeter notation the half symmetry is [3,3,8,1+] = [3,((3,4,3))].
Infinite-order tetrahedral honeycomb
| Infinite-order tetrahedral honeycomb | |
|---|---|
| Type | Hyperbolic regular honeycomb | 
| Schläfli symbols | {3,3,∞} {3,(3,∞,3)} | 
| Coxeter diagrams |               =       | 
| Cells | {3,3}  | 
| Faces | {3} | 
| Edge figure | {∞} | 
| Vertex figure | {3,∞}  {(3,∞,3)}  | 
| Dual | {∞,3,3} | 
| Coxeter group | [∞,3,3] [3,((3,∞,3))] | 
| Properties | Regular | 
In the geometry of hyperbolic 3-space, the infinite-order tetrahedral honeycomb is a regular space-filling tessellation (or honeycomb) with Schläfli symbol {3,3,∞}. It has infinitely many tetrahedra {3,3} around each edge. All vertices are ultra-ideal (existing beyond the ideal boundary) with infinitely many tetrahedra existing around each vertex in an infinite-order triangular tiling vertex arrangement.
|  Poincaré disk model (cell-centered) |  Rendered intersection of honeycomb with the ideal plane in Poincaré half-space model | 
It has a second construction as a uniform honeycomb, Schläfli symbol {3,(3,∞,3)}, Coxeter diagram, 





 =
 = 




 , with alternating types or colors of tetrahedral cells. In Coxeter notation the half symmetry is [3,3,∞,1+] = [3,((3,∞,3))].
, with alternating types or colors of tetrahedral cells. In Coxeter notation the half symmetry is [3,3,∞,1+] = [3,((3,∞,3))].
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)
- The Beauty of Geometry: Twelve Essays (1999), Dover Publications, LCCN 99-35678, ISBN 0-486-40919-8 (Chapter 10, Regular Honeycombs in Hyperbolic Space) Table III
- Jeffrey R. Weeks The Shape of Space, 2nd edition ISBN 0-8247-0709-5 (Chapters 16–17: Geometries on Three-manifolds I,II)
- George Maxwell, Sphere Packings and Hyperbolic Reflection Groups, JOURNAL OF ALGEBRA 79,78-97 (1982)
- Hao Chen, Jean-Philippe Labbé, Lorentzian Coxeter groups and Boyd-Maxwell ball packings, (2013)
- Visualizing Hyperbolic Honeycombs arXiv:1511.02851 Roice Nelson, Henry Segerman (2015)
External links
- John Baez, Visual insights: {7,3,3} Honeycomb (2014/08/01) {7,3,3} Honeycomb Meets Plane at Infinity (2014/08/14)
- Danny Calegari, Kleinian, a tool for visualizing Kleinian groups, Geometry and the Imagination 4 March 2014.