Color groups arising from index-nsubgroups of symmetry groups

Abstract

One of the main goals in the study of color symmetry is to classify colorings of symmetrical objects through their color groups. The term color group is taken to mean the subgroup of the symmetry group of the uncolored symmetrical object which induces a permutation of colors in the coloring. This work looks for methods of determining the color group of a colored symmetric object. It begins with an indexnsubgroupHof the symmetry groupGof the uncolored object. It then considersH-invariant colorings of the object, so that the color groupH*will be a subgroup ofGcontainingH. In other words,H≤H*≤G. It proceeds to give necessary and sufficient conditions for the equality ofH*andG. IfH*≠Gandnis prime, thenH*=H. On the other hand, ifH*≠Gandnis not prime, methods are discussed to determine whetherH*isG,Hor some intermediate subgroup betweenHandG.