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Graphs characterized by the second eigenvalue
Author(s) -
Cao Dasong,
Yuan Hong
Publication year - 1993
Publication title -
journal of graph theory
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 54
eISSN - 1097-0118
pISSN - 0364-9024
DOI - 10.1002/jgt.3190170307
Subject(s) - combinatorics , mathematics , vertex (graph theory) , graph , eigenvalues and eigenvectors , simple graph , discrete mathematics , physics , quantum mechanics
In this paper we prove that for a simple graph G without isolated vertices 0 < λ 2 ( G ) < 1/3 if and only if G ≅ K̄ n ‐3 V ( K 1 ∪ K 2 ), the graph obtained by joining each vertex of K̄ n ‐3 to each vertex of K 1 ∪ K 2 ). © 1993 John Wiley & Sons, Inc.