ISI Energy Change Due to an Edge Deletion

The problem of characterization of all graphs where the deletion of an edge results in decrease or increase in the energy is far from completion. To be more exact, we solve this problem for Inverse Sum Indeg energy. We compute the ISI energies of edge deleted graphs of K-n, K-n,K-n, K-n,K-n,K-n, and star graph, finally we compare the respective energies from the original graphs. We give different graphs where both cases can happen. This serves as partial solutions of the modified version of the hard to crack problem posed by Gutman to characterize all graphs whose energy decreases after deletion of an edge.