The Spectral Excess Theorem for Distance-Regular Graphs: A Global (Over)view
The Spectral Excess Theorem for Distance-Regular Graphs: A Global (Over)view
Distance-regularity of a graph is in general not determined by the spectrum of the graph. The spectral excess theorem states that a connected regular graph is distance-regular if for every vertex, the number of vertices at extremal distance (the excess) equals some given expression in terms of the spectrum of …