Signed line graphs with least eigenvalue -2: The star complement technique

نویسندگان

  • Francesco Belardo
  • Enzo Maria Li Marzi
  • Slobodan K. Simic
چکیده

Let G be a connected graph with least eigenvalue −2, of multiplicity k. A star complement for −2 in G is an induced subgraph H = G − X such that |X | = k and −2 is not an eigenvalue of H . In the case that G is a generalized line graph, a characterization of such subgraphs is used to decribe the eigenspace of −2. In some instances, G itself can be characterized by a star complement. If G is not a generalized line graph, G is an exceptional graph, and in this case it is shown how a star complement can be used to construct G without recourse to root systems.

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عنوان ژورنال:
  • Discrete Applied Mathematics

دوره 207  شماره 

صفحات  -

تاریخ انتشار 2016