On Cayley Graphs of Inverse Semigroups

We describe all finite inverse semigroups and all commutative inverse semigroups with bipartite Cayley graphs. Examples are given which show that this description does not generalize to arbitrary inverse semigroups. Next, we describe all inverse epigroups with Cayley graphs which are disjoint unions of complete graphs. The example of Baer-Levi semigroups shows that it is impossible to drop the condition that G be inverse from this theorem. © 2006 Springer.