On locally spherical polytopes of type {5, 3, 5}

Abstract

There are only finitely many locally projective regular polytopes of type {5, 3, 5}. They are covered by a locally spherical polytope whose automorphism group is J 1 × J 1 × L 2 ( 19 ) , where J 1 is the first Janko group, of order 175560, and L 2 ( 19 ) is the projective special linear group of order 3420. This polytope is minimal, in the sense that any other polytope that covers all locally projective polytopes of type {5, 3, 5} must in turn cover this one.