Î²-Differential of a GraphLudwin A. Basilio, Sergio Bermudo, JesÃºs LeaÃ±os, Jose Maria SigarretaSymmetry2017Let G = (V, E) be a simple graph with vertex set V and edge set E. Let D be a subset of V, and let B(D) be the set of neighbours of D in V \ D. The differential âˆ‚(D) of D is defined as |B(D)| âˆ’ |D|.â€¦ (More)