Regular collaborations with : - Serge Bouc, Université de Picardie Jules Verne, Amiens - Jon F. Carlson, University of Georgia, USA - Nadia Mazza, University of Lancaster, GB - Radu Stancu, Université de Picardie Jules Verne, Amiens

- Representations of finite groups : Modular representations, endo-permutation modules, endo-trivial modules, block theory, G-algebras, p-local theory, Alperin's conjecture, almost split sequences, Clifford theory, representations in characteristic p^r. - Mackey functors and biset functors : Structure theory, simple functors, G-algebras, cohomology, representation rings. - Posets of subgroups of finite groups : Moebius function, Euler characteristic, Burnside rings. - Finite simplicial complexes : Brown's and Quillen's complexes, Tits buildings, subgroup complexes, topological K-theory.