The spectral radius of subgraphs of regular graphs

Abstract

Let μ (G) and μmin (G) be the largest and smallest eigenvalues of the adjacency-matrix of a graph G. Our main results are: (i) Let G be a regular graph of order n and finite diameter D. If H is a proper subgraph of G, then μ(G)-μ(H) > 1/nD. (ii) If G is a regular nonbipartite graph of order n and finite diameter D, then μ (G) +μmin (G) 1/nD.

Publication Title

Electronic Journal of Combinatorics

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