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s |- |bgcolor=#e7dcc3|Coxeter-Dynkin diagram |colspan=2| = |- |bgcolor=#e7dcc3|4-faces||26||10 16 |- |bgcolor=#e7dcc3|Cells||120||40 80 |- |bgcolor=#e7dcc3|Faces||160|| |- |bgcolor=#e7dcc3|Edges||colspan=2|80 |- |bgcolor=#e7dcc3|Vertices||colspan=2|16 |- |bgcolor=#e7dcc3|Vertex figure |colspan=2|60px rectified 5-cell |- |bgcolor=#e7dcc3|Petrie polygon |colspan=2|Octagon |- |bgcolor=#e7dcc3|Symmetry group |colspan=2|D5, () = () ()+ |- |bgcolor=#e7dcc3|Properties |colspan=2|convex |} In five-dimensional geometry, a demipenteract or 5-demicube is a semiregular 5-polytope, constructed from a ''5-hypercube'' (penteract) with alternated vertices truncated. It was discovered by Thorold Gosset. Since it was the only semiregular 5-polytope (made of more than one type of regular facets), he called it a 5-ic semi-regular. E. L. Elte identified it in 1912 as a semiregular polytope, labeling it as HM5 for a 5-dimensional ''half measure'' polytope. Coxeter named this polytope as 121 from its Coxeter diagram, which has branches of length 2, 1 and 1 with a ringed node on one of the short branches, and Schläfli symbol or . It exists in the k21 polytope family as 121 with the Gosset polytopes: 221, 321, and 421. The graph formed by the vertices and edges of the demipenteract is sometimes called the Clebsch graph, though that name sometimes refers to the folded cube graph of order five instead. == Cartesian coordinates == Cartesian coordinates for the vertices of a demipenteract centered at the origin and edge length 2√2 are alternate halves of the penteract: : (±1,±1,±1,±1,±1) with an odd number of plus signs. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「5-demicube」の詳細全文を読む スポンサード リンク
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