Local Symmetries for Molecular Graphs

Local graph symmetry groups are formally defined as acting in a non-identical fashion on just a proper (local) subset of a graph's vertices, and consequent theorems are established for adjacency matrices so as to simplify eigensolutions. These groups sometimes enlarging on the usual point groups, are illustrated, with examples of the application of the theorems. Some discussion of further utility, on elaborated models & on identification of so-called "accidental" degeneracies, is indicated.