Bounds on the regularity of toric ideals of graphs

Abstract Let G be a finite simple graph. We give a lower bound for the Castelnuovo–Mumford regularity of the toric ideal I G associated to G in terms of the sizes and number of induced complete bipartite graphs in G . When G is a chordal bipartite graph, we find an upper bound for the regularity of I G in terms of the size of the bipartition of G . We also give a new proof for the graded Betti numbers of the toric ideal associated to the complete bipartite graph K 2 , n .