Michael Baake, Uwe Grimm, Max Scheffer
Tilings colourful - only even more so
(227K, LaTeX using autart.cls, one colour Postscript figure included)
ABSTRACT. We consider colour symmetries for planar tilings of certain n-fold rotational symmetry. The colourings are such that one colour occupies a submodule of n-fold symmetry, while the other colours encode the cosets. We determine the possible number of colours and count inequivalent colouring solutions with those numbers. The corresponding Dirichlet series generating functions are zeta functions of cyclotomic fields. The cases with phi(n)<=8, where phi is Euler's totient function, have been completely presented in previous publications. The same methods can be employed to extend the classification to all cases where the cyclotomic integers have class number one. Several examples for symmetries with phi(n)>8 are discussed here.