Projective‐planar graphs with even duals
Seiya Negami · Journal of Graph Theory · 1992
Abstract Let G be a connected graph which is projective‐planar but is not planar. It will be shown that G can be embedded in the projective plane so that it has only even faces if and only if either G is bipartite or its canonical bipartite covering is planar and that such an embedding is unique if G is 3‐connected.