Are almost all graphs determined by their spectrum?

  • Aida Abiad (Ghent University/Maastricht University, Maastricht, Netherlands)
E1 05 (Leibniz-Saal)


In this talk we will look at the spectrum (eigenvalues) of the adjacency matrix of a graph, and ask whether the eigenvalues determine the graph. This is a difficult, but important problem which plays a special role in the famous graph isomorphism problem. It has been conjectured by van Dam and Haemers that almost every graph is determined by its spectrum. The mentioned problem has been solved for several families of graphs; sometimes by proving that the spectrum determines the graph, and sometimes by constructing nonisomorphic graphs with the same spectrum. In recent years this problem has attracted much interest. In this talk we will report on recent results concerning this conjecture.

Valeria Hünniger

Max Planck Institute for Mathematics in the Sciences Contact via Mail

Francesca Arici

Radboud University Nijmegen

Tatjana Eisner

Leipzig University

Barbara Gentz

University of Bielefeld

Angkana Rüland

Max Planck Institute for Mathematics in the Sciences

Rebecca Waldecker

Martin-Luther-University Halle-Wittenberg

Milena Wrobel

Carl von Ossietzky Universität Oldenburg