- Gosset 3 21 polytope
In 7-dimensional
geometry , the 321 is asemiregular polytope , enumerated byThorold Gosset in his 1900 paper. He called it an "7-ic semi-regular figure". It is called the Hess polytope forEdmund Hess who first discovered it.Its construction is based on the E7 group.
Coxeter named it as 321 by its bifurcatingCoxeter-Dynkin diagram , with a single ring on the end of the 3-node sequence.It is also one of a family of 127 (27-1) convex
uniform polytope s in 7-dimensions, made ofuniform polytope facets andvertex figure s, defined by all permutations of rings in thisCoxeter-Dynkin diagram : :This polytope, along with the
7-simplex , can tessellate 7-dimensional space, represented by 331 andCoxeter-Dynkin diagram ::.References
* T. Gosset: "On the Regular and Semi-Regular Figures in Space of n Dimensions", Messenger of Mathematics, Macmillan, 1900
* A. Boole Stott: "Geometrical deduction of semiregular from regular polytopes and space fillings", Verhandelingen of the Koninklijke academy van Wetenschappen width unit Amsterdam, Eerste Sectie 11,1, Amsterdam, 1910
** 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, ISBN 978-0-471-01003-6 [http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471010030.html]
** (Paper 24) H.S.M. Coxeter, "Regular and Semi-Regular Polytopes III", [Math. Zeit. 200 (1988) 3-45] See p342 (figure 3.7c) by Peter mcMullen: (18-gonal node-edge graph of 321)See also
*
7-polytope
*Semiregular k 21 polytope
*Gosset 1 32 polytope
*Gosset 2 31 polytope
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