Asymptotic results on Betti numbers of edge ideals of graphs

Title: Asymptotic results on Betti numbers of edge ideals of graphs via critical graphs

Abstract: To any graph G one can associate its edge ideal. One of the most famous results in combinatorial commutative algebra, Hochster's formula, describes the Betti numbers of the edge ideal in terms of combinatorial information on the graph G. More explicitly, each specific Betti number is given in terms of the presence of certain induced subgraphs in G. The machinery of critical graphs, relatively recently introduced by Balogh and Butterfield, deals with characterizing asymptotically the structure of graphs based on their induced subgraphs. In a joint work with Alexander Engström, we apply these techniques to Betti numbers and regularity of edge ideals. We introduce parabolic Betti numbers, which constitute a non-trivial portion of the Betti table. Usually, the vanishing of a Betti number has little impact on the rest of the Betti table. I this talk I will describe our main results, which show that on the other hand the vanishing of a parabolic Betti number determines asymptotically the structure and regularity of the graphs with that Betti number equal to zero.

To receive the Zoom link, please contact Victor Falgas Ravry.