- List of uniform polyhedra by vertex figure
There are many relations among the
uniform polyhedron .Some are obtained by truncating the vertices of the regular or quasi-regular polyhedron.Others share the same vertices and edges as other polyhedron.The grouping below exhibit some of these relations.The vertex figure of a polyhedron
The relations can be made apparent by examining the
vertex figure s.obtained by listing the faces adjacent to each vertex (remember that for uniform polyhedra all vertices are the same, that isvertex-transitive ). For example the cube hasvertex figure 4.4.4 that is three adjacent square faces.The possible faces are
* 3 - equilateral triangle
* 4 - square
* 5 - regular pentagon
* 6 - regular hexagon
* 8 - regular octagon
*10 - regular decagon
* 5/2 - pentagram
* 8/3 - octagram
* 10/3 - decagramSome faces will appear with reverse orientation which is written here as
* -3 - a triangle with reverse orientation (often written as 3/2)Others pass through the origin which we write as
* 6* - hexagon passing through the originThe
Wythoff symbol relates the polyhedron to spherical triangles. Wythoff symbols are writtenp|q r, p q|r, p q r| where the spherical triangle has angles π/p,π/q,π/r, the bar indicates the position of the vertices in relation to the triangle.Johnson (2000) classified uniform polyhedra according to the following:
# Regular (regular polygonal vertex figures): pq, Wythoff symbol q|p 2
# Quasi-regular (rectangular or ditrigonal vertex figures): p.q.p.q 2|p q, or p.q.p.q.p.q, Wythoff symbol 3|p q
# Versi-regular (orthodiagonal vertex figures), p.q*.-p.q*, Wythoff symbol q q|p
# Truncated regular (isosceles triangular vertex figures): p.p.q, Wythoff symbol q 2|p
# Versi-quasi-regular (dipteroidal vertex figures), p.q.p.r Wythoff symbol q r|p
# Quasi-quasi-regular (trapezoidal vertex figures): p*.q.p*.-r q.r|p or p.q*.-p.q* p q r
# Truncated quasi-regular (scalene triangular vertex figures), p.q.r Wythoff symbol p q r
# Snub quasi-regular (pentagonal, hexagonal, or octagonal vertex figures), Wythoff symbol p q r
# Prisms (truncated hosohedra),
# Antiprisms and crossed antiprisms (snub dihedra)The format of each figure follows the same basic pattern
# image of polyhedron
# name of polyhedron
# alternate names (in brackets)
# Wythoff symbol
# Numbering systems: W - number used by Wenninger in "polyhedra models", U - uniform indexing, K - Kaleido indexing, C - numbering used in Coxeter "et al." 'Uniform Polyhedra'.
# Number of vertices V, edges E, Faces F and number of faces by type.
# Euler characteristic χ = V - E + F The vertex figures are on the left, followed by thePoint groups in three dimensions#The seven remaining point groups , either tetrahedral Td, octahedral Oh or icosahedral Ih.Truncated forms
Regular polyhedra and their truncated forms
Column A lists all the regular polyhedra,column B list their truncated forms.Regular polyhedra all have vertex figures pr: p.p.p etc. and Whycroft symbolpq r. The truncated forms have vertex figure q.q.r (where q=2p and r) and Whycroft p qr.
Polyhedra sharing edges and vertices
Regular
These are all mentioned elsewhere, but this table shows some relations.They are all regular apart from the tetrahemihexahedron which is versi-regular.
versi-quasi-regular and quasi-quasi-regular
Group III: trapezoid or crossed trapezoid vertex figures.The first column include the convex rhombic polyhedra, created by inserting two squaresinto the vertex figures of the Cuboctahedron and Icosidodecahedron.
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