%0 Journal Article
%T Median eigenvalues of bipartite subcubic graphs
%A Bojan Mohar
%J Mathematics
%D 2013
%I arXiv
%X It is proved that the median eigenvalues of every connected bipartite graph $G$ of maximum degree at most three belong to the interval $[-1,1]$ with a single exception of the Heawood graph, whose median eigenvalues are $\pm\sqrt{2}$. Moreover, if $G$ is not isomorphic to the Heawood graph, then a positive fraction of its median eigenvalues lie in the interval $[-1,1]$. This surprising result has been motivated by the problem about HOMO-LUMO separation that arises in mathematical chemistry.
%U http://arxiv.org/abs/1309.7395v1