Groups Generated by Unitary Reflections of Period Two

Abstract

In complex affine n-space with a unitary metric, a reflection is a congruent transformation leaving invariant all the points of a hyperplane. Thus the characteristic roots of a unitary reflection of period p consist of a primitive pth root of unity and n – 1 unities. A group generated by n reflections is conveniently represented by a graph having a node for each generator and a branch for each pair of non-commutative generators.