STABLE VALUE OF DEPTH OF SYMBOLIC POWERS OF EDGE IDEALS OF GRAPHS

Let G be a simple graph on n vertices. We introduce the notion of bipartite connectivity of G , denoted by bc ( G ) and prove that lim s ->infinity depth ( S / I ( G ) ( s ) ) <= bc ( G ), where I ( G ) denotes the edge ideal of G and S = k [ x 1 , . . . , x n ] is a standard graded polynomial ring over a field k. We further compute the depth of symbolic powers of edge ideals of several classes of graphs, including odd cycles and whisker graphs of complete graphs to illustrate the cases where the above inequality becomes equality.