Maximum genus embeddings of Steiner triple systems

We prove that for <f>n>3</f> every <f>STS(n)</f> has both an orientable and a nonorientable embedding in which the triples of the <f>STS(n)</f> appear as triangular faces and there is just one additional large face. We also obtain detailed results about the possible automorphisms of such embeddings. [Copyright &y& Elsevier]