The energy $E(G)$ of a graph $G$ is defined as the sum of the absolute values of its eigenvalues. Let $S_2$ be the star of order 2 (or $K_2$) and $Q$ be the graph obtained from $S_2$ by attaching two pendent edges to each of the end vertices of $S_2$. Majstorovi\'c et al. conjectured that $S_2$, $Q$ and the complete bipartite graphs $K_{2,2}$ and $K_{3,3}$ are the only 4 connected graphs with maximum degree $\Delta \leq 3$ whose energies are equal to the number of vertices. This paper is devoted to giving a confirmative proof to the conjecture.Comment: 17 page

Topics:
Mathematics - Combinatorics, 15A18, 05C50, 05C90, 92E10

Year: 2009

OAI identifier:
oai:arXiv.org:0907.1341

Provided by:
arXiv.org e-Print Archive

Downloaded from
http://arxiv.org/abs/0907.1341

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