Monomial ideals arising from flag complexes whose generic initial ideals do not depend on term orders

Abstract

We will study monomial ideals $I$ in the exterior algebra as well as in the polynomial ring whose generic initial ideal is constant for all term orders up to permutations of variables. First, in the exterior algebra, we determine all graphs and all flag complexes whose exterior face ideal satisfies the above condition. Second, in the polynomial ring, it will be shown that the generic initial ideal $\gin_\sigma(I(G))$ of the edge ideal $I(G)$ of a graph $G$ is constant for all term orders $\sigma$ up to permutations of variables if and only if $G$ is a complete bipartite graph.