Delta matroids whose fundamental graphs are bipartite (Q1183130)

The delta matroids are generalizations of matroids; they are defined by replacing the minus sign by the symmetric difference sign in the base exchange axiom. Their fundamental graph with respect to a given base \(F\) is defined so that the underlying set becomes the vertex set and two vertices \(x,y\) are adjacent if and only if \(F\Delta\{x,y\}\) is a base. A delta matroid is even if the symmetric difference of any two bases has even cardinality. A. Bouchet proved that an even delta matroid is a matroid if only if its fundamental graph is bipartite. This paper gives an excluded minor characterization of those (not necessarily even) delta matroids which have bipartite fundamental graphs.