Symbolic defects of edge ideals of unicyclic graphs

Abstract

We introduce the concept of minimum edge cover for an induced subgraph in a graph. Let $G$ be a unicyclic graph with a unique odd cycle and $I=I(G)$ be its edge ideal. We compute the exact values of all symbolic defects of $I$ using the concept of minimum edge cover for an induced subgraph in a graph. We describe one method to find the quasi-polynomial associated with the symbolic defects of edge ideal $I$. We classify the class of unicyclic graphs when some power of maximal ideal annihilates $I^{(s)}/I^s$ for any fixed $s$. Also for those class of graphs, we compute the Hilbert function of the module $I^{(s)}/I^s$ for all $s.$