International Journal of Combinatorics
Volume 2011 (2011), Article ID 787596, 11 pages
Research Article

Beyond the Expanders

Institute of Mathematics, Budapest University of Technology and Economics, Egry József u. 1, 1111 Budapest, Hungary

Received 31 January 2011; Accepted 29 April 2011

Academic Editor: R. Yuster

Copyright © 2011 Marianna Bolla. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Expander graphs are widely used in communication problems and construction of error correcting codes. In such graphs, information gets through very quickly. Typically, it is not true for social or biological networks, though we may find a partition of the vertices such that the induced subgraphs on them and the bipartite subgraphs between any pair of them exhibit regular behavior of information flow within or between the vertex subsets. Implications between spectral and regularity properties are discussed.