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Polyhedron Coloring


Polyhedron coloring assigns colors to the faces of a polyhedron. A proper coloring requires that no two faces with a common polyhedron edge share the same color. In the counts below, the colors are distinguished and colorings related by a rotation of the regular polyhedron are identified. Mirror image colorings are counted separately unless a rotation identifies them.

Given two colors, there is a single proper coloring of an octahedron (Ball and Coxeter 1987, pp. 238-239). Given three colors, there is one proper coloring of a cube (Ball and Coxeter 1987, pp. 238-239) and 144 of an icosahedron (Ball and Coxeter 1987, pp. 239-242). Given four colors, there are two proper colorings of a tetrahedron (Ball and Coxeter 1987, p. 238) and four of a dodecahedron, consisting of two enantiomorphous pairs (Ball and Coxeter 1987, p. 238; Steinhaus 1999, pp. 196-198). There are four colorings of an icosahedron with five colors under the stronger requirement that the five faces incident to each vertex all have different colors (Makai and Tarnai 2021). There are 30 colorings of a cube in which each of its six faces has a different color (Steinhaus 1999, p. 167). The chromatic polynomial of the dual graph of a polyhedron's skeleton counts proper colorings before identifying those related by rotations. Additional restrictions, such as requiring all faces at a vertex to have different colors, are not imposed by this chromatic polynomial.

The following table gives the numbers of ways to color the faces of the Platonic solids using at most n colors, with no restriction on the colors of adjacent faces. The colors remain distinguished and colorings related by rotations are identified. The counts follow from the group action of the rotational symmetry group on the faces using the Pólya enumeration theorem.

solidpolynomialOEIScolorings for n=1, 2, ...
cube1/3n^2+1/2n^3+1/8n^4+1/(24)n^6A0477801, 10, 57, 240, 800, 2226, 5390, ...
dodecahedron(11)/(15)n^4+1/4n^6+1/(60)n^(12)A0005451, 96, 9099, 280832, 4073375, 36292320, ...
icosahedron2/5n^4+1/3n^8+1/4n^(10)+1/(60)n^(20)A0544721, 17824, 58130055, 18325477888, 1589459765875, ...
octahedron1/4n^2+(17)/(24)n^4+1/(24)n^8A0005431, 23, 333, 2916, 16725, 70911, 241913, ...
tetrahedron(11)/(12)n^2+1/(12)n^4A0060081, 5, 15, 36, 75, 141, 245, 400, 621, ...

See also

Chromatic Polynomial, Coloring, Cube, Dodecahedron, Graph Coloring, Icosahedron, Octahedron, Platonic Solid, Pólya Enumeration Theorem, Polyhedron, Tetrahedron

Portions of this entry contributed by Oyvind Tafjord

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References

Ball, W. W. R. and Coxeter, H. S. M. Mathematical Recreations and Essays, 13th ed. New York: Dover, pp. 238-242, 1987.Cundy, H. and Rollett, A. Mathematical Models, 3rd ed. Stradbroke, England: Tarquin Pub., pp. 82-83, 1989.Makai, E. Jr. and Tarnai, T. "A Colouring Problem for the Dodecahedral Graph." Elem. Math. 76, 1-9, 2021. https://doi.org/10.4171/EM/422.Sloane, N. J. A. Sequences A000543, A000545, A006008/M3854, A047780/M4716, and A054472 in "The On-Line Encyclopedia of Integer Sequences."Steinhaus, H. Mathematical Snapshots, 3rd ed. New York: Dover, 1999.

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Polyhedron Coloring

Cite this as:

Weisstein, Eric W., with contributions by Oyvind Tafjord. "Polyhedron Coloring." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PolyhedronColoring.html

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