A characterization of circle graphs in terms of total unimodularity Universiteit Hasselt
A graph G has an associated multimatroid Z(3)(G), which is equivalent to the isotropic system of G studied by Bouchet. In previous work it was shown that G is a circle graph if and only if for every field F, the rank function of Z(3)(G) can be extended to the rank function of an F-representable matroid. In the present paper we strengthen this result using a multimatroid analogue of total unimodularity. As a consequence we obtain a ...