Tullio Ceccherini-Silberstein, Universita` del Sannio
Large Conference Room, Math Building
We discuss several aspects of amenability and non-amenability for groups, graphs, and metric spaces. The central result is Tarski alternative theorem (amenability is equivalent to absence of paradoxical decompositions). Bipartite graphs and the harem version of the Rado-Hall marriage theorem (a central result for the proof of the alternative theorem) will also be discussed.