ON COMPUTING A SPECIAL CLASS OF IRREDUCIBLE NON-EMBEDDED GRAPHS FOR THE PROJECTIVE PLANE II

Abstract

This paper is a continuation of [2], presenting some more results leading to establishing a complete list of irreducible non-embeddable graphs for the projective plane. The main result presented here is the following theorem: all irreducible non-embeddable graphs for the projective plane which have a subgraph contractable to $E sub 2$ and do not have a subgraph contractable to $E sub 1$ or $GAMMA sub 1$ or $K sub 3,4$ are contractable to one of the 3 graphs $F sub 3, F sub 4$ or $E sub 20$ in [E].