B4 polytope
From Wikipedia, the free encyclopedia
In 4-dimensional geometry, there are 15 uniform 4-polytopes with B4 symmetry. There are two regular forms, the tesseract and 16-cell, with 16 and 8 vertices respectively.
 Tesseract     |
 16-cell |
Visualizations
They can be visualized as symmetric orthographic projections in Coxeter planes of the B5 Coxeter group, and other subgroups.
Symmetric orthographic projections of these 32 polytopes can be made in the B5, B4, B3, B2, A3, Coxeter planes. Ak has [k+1] symmetry, and Bk has [2k] symmetry.
These 32 polytopes are each shown in these 5 symmetry planes, with vertices and edges drawn, and vertices colored by the number of overlapping vertices in each projective position.
The pictures are drawn as Schlegel diagram perspective projections, centered on the cell at pos. 3, with a consistent orientation, and the 16 cells at position 0 are shown solid, alternately colored.
| # | Name | Coxeter plane projections | Schlegel diagrams |
Net | ||||
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| B4 [8] |
B3 [6] |
B2 [4] |
A3 [4] |
Cube centered |
Tetrahedron centered | |||
| 1 | 8-cell or tesseract = {4,3,3} |
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| 2 | rectified 8-cell = r{4,3,3} |
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| 3 | 16-cell = {3,3,4} |
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| 4 | truncated 8-cell = t{4,3,3} |
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| 5 | cantellated 8-cell = rr{4,3,3} |
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| 6 | runcinated 8-cell (also runcinated 16-cell) = t03{4,3,3} |
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| 7 | bitruncated 8-cell (also bitruncated 16-cell) = 2t{4,3,3} |
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| 8 | truncated 16-cell = t{3,3,4} |
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| 9 | cantitruncated 8-cell = tr{3,3,4} |
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| 10 | runcitruncated 8-cell = t013{4,3,3} |
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| 11 | runcitruncated 16-cell = t013{3,3,4} |
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| 12 | omnitruncated 8-cell (also omnitruncated 16-cell) = t0123{4,3,3} |
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| # | Name | Coxeter plane projections | Schlegel diagrams |
Net | |||||
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| F4 [12] |
B4 [8] |
B3 [6] |
B2 [4] |
A3 [4] |
Cube centered |
Tetrahedron centered | |||
| 13 | *rectified 16-cell (Same as 24-cell) = r{3,3,4} = {3,4,3} |
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| 14 | *cantellated 16-cell (Same as rectified 24-cell) = rr{3,3,4} = r{3,4,3} |
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| 15 | *cantitruncated 16-cell (Same as truncated 24-cell) = tr{3,3,4} = t{3,4,3} |
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| # | Name | Coxeter plane projections | Schlegel diagrams |
Net | |||||
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| F4 [12] |
B4 [8] |
B3 [6] |
B2 [4] |
A3 [4] |
Cube centered |
Tetrahedron centered | |||
| 16 | alternated cantitruncated 16-cell (Same as the snub 24-cell)  = sr{3,3,4} = s{3,4,3} |
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Coordinates
The tesseractic family of 4-polytopes are given by the convex hulls of the base points listed in the following table, with all permutations of coordinates and sign taken. Each base point generates a distinct uniform 4-polytopes. All coordinates correspond with uniform 4-polytopes of edge length 2.
| # | Base point | Name | Coxeter diagram | Vertices | |
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| 3 | (0,0,0,1)√2 | 16-cell | |
8 | 24-34!/3! |
| 1 | (1,1,1,1) | Tesseract | |
16 | 244!/4! |
| 13 | (0,0,1,1)√2 | Rectified 16-cell (24-cell) | |
24 | 24-24!/(2!2!) |
| 2 | (0,1,1,1)√2 | Rectified tesseract | |
32 | 244!/(3!2!) |
| 8 | (0,0,1,2)√2 | Truncated 16-cell | |
48 | 24-24!/2! |
| 6 | (1,1,1,1) + (0,0,0,1)√2 | Runcinated tesseract | |
64 | 244!/3! |
| 4 | (1,1,1,1) + (0,1,1,1)√2 | Truncated tesseract | |
64 | 244!/3! |
| 14 | (0,1,1,2)√2 | Cantellated 16-cell (rectified 24-cell) | |
96 | 244!/(2!2!) |
| 7 | (0,1,2,2)√2 | Bitruncated 16-cell | |
96 | 244!/(2!2!) |
| 5 | (1,1,1,1) + (0,0,1,1)√2 | Cantellated tesseract | |
96 | 244!/(2!2!) |
| 15 | (0,1,2,3)√2 | cantitruncated 16-cell (truncated 24-cell) | |
192 | 244!/2! |
| 11 | (1,1,1,1) + (0,0,1,2)√2 | Runcitruncated 16-cell | |
192 | 244!/2! |
| 10 | (1,1,1,1) + (0,1,1,2)√2 | Runcitruncated tesseract | |
192 | 244!/2! |
| 9 | (1,1,1,1) + (0,1,2,2)√2 | Cantitruncated tesseract | |
192 | 244!/2! |
| 12 | (1,1,1,1) + (0,1,2,3)√2 | Omnitruncated 16-cell | |
384 | 244! |
References
- J.H. Conway and M.J.T. Guy: Four-Dimensional Archimedean Polytopes, Proceedings of the Colloquium on Convexity at Copenhagen, pp. 38–39, 1965
- John H. Conway, Heidi Burgiel, Chaim Goodman-Strauss, The Symmetries of Things 2008, ISBN 978-1-56881-220-5 (Chapter 26)
- H.S.M. Coxeter:
- H.S.M. Coxeter, Regular Polytopes, 3rd Edition, Dover, New York, 1973
- Kaleidoscopes: Selected Writings of H.S.M. Coxeter, edited by F. Arthur Sherk, Peter McMullen, Anthony C. Thompson, Asia Ivic Weiss, Wiley-Interscience Publication, 1995, wiley.com, ISBN 978-0-471-01003-6
- (Paper 22) H.S.M. Coxeter, Regular and Semi-Regular Polytopes I, [Math. Zeit. 46 (1940) 380–407, MR 2,10]
- (Paper 23) H.S.M. Coxeter, Regular and Semi-Regular Polytopes II, [Math. Zeit. 188 (1985) 559–591]
- (Paper 24) H.S.M. Coxeter, Regular and Semi-Regular Polytopes III, [Math. Zeit. 200 (1988) 3–45]
- N.W. Johnson: The Theory of Uniform Polytopes and Honeycombs, Ph.D. Dissertation, University of Toronto, 1966
External links
- Klitzing, Richard. "4D uniform polytopes (polychora)".
- Uniform, convex polytopes in four dimensions, Marco Möller (in German)
- Möller, Marco (2004). Vierdimensionale Archimedische Polytope (PDF) (Doctoral dissertation) (in German). University of Hamburg.
- Uniform Polytopes in Four Dimensions, George Olshevsky.
- Convex uniform polychora based on the tesserract/16-cell, George Olshevsky.