Order-7 tetrahedral honeycomb
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.
| 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 | 
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 | ![]()  | 
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| 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} | 
|---|---|---|---|---|---|---|
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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, ![]()
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, 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, ![]()
![]()
![]()
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![]()
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 = ![]()
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, with alternating types or colors of tetrahedral cells. In Coxeter notation the half symmetry is [3,3,∞,1+] = [3,((3,∞,3))].
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.
 






















