Boguñá, MariánPastor-Satorras, R. (Romualdo), 1967-Vespignani, Alessandro, 1965-2010-07-052010-07-0520030031-9007https://hdl.handle.net/2445/13251Random scale-free networks have the peculiar property of being prone to the spreading of infections. Here we provide for the susceptible-infected-susceptible model an exact result showing that a scale-free degree distribution with diverging second moment is a sufficient condition to have null epidemic threshold in unstructured networks with either assortative or disassortative mixing. Degree correlations result therefore irrelevant for the epidemic spreading picture in these scale-free networks. The present result is related to the divergence of the average nearest neighbors degree, enforced by the degree detailed balance condition.4 p.application/pdfeng(c) American Physical Society, 2003Mecànica estadísticaFísica estadísticaStatistical mechanicsStatistical physicsinfo:eu-repo/semantics/article514080info:eu-repo/semantics/openAccess