The edge-transitive polytopes that are not vertex-transitive

Abstract

In 3-dimensional Euclidean space there exist two exceptional polyhedra, the rhombic dodecahedron and the rhombic triacontahedron, the only known polytopes (besides polygons) that are edge-transitive without being vertex-transitive. We show that these polyhedra do not have higher-dimensional analogues, that is, that in dimension d ≥ 4, edge-transitivity of convex polytopes implies vertex-transitivity.More generally, we give a classification of all convex polytopes which at the same time have all edges of the same length, an edge in-sphere and a bipartite edge-graph. We show that any such polytope in dimension d ≥ 4 is vertex-transitive.