“…[11,12,13,17,18,19,20,21,22,23,24,28,26,27]), and hierarchical extensions of the node degree and clustering coefficient were only more recently formalized in [9,10] by using concepts derived from mathematical morphology [25,29,30] including dilations and distance transforms in graphs. Despite their recent introduction, such concepts have already yielded valuable results when applied to essentiality of protein-protein interaction networks [37], bone structure characterization [38], and community finding [32,33].…”