Faculté des géosciences et de l'environnement

## Investigation phytochimique d'une brosse à dents africaine "Zanthoxylum zanthoxyloides" (Lam.) Zepernick et Timler (Syn. "Fagara zanthoxiloides" L.) (Rutaceae)

### Thèse de doctorat : Université de Lausanne, 2004.

By the work of H. Cartan, it is well known that one can find elements of arbitrarilly high torsion in the integral (co)homology groups of an Eilenberg-MacLane space K(G, n), where G is a non-trivial abelian group and n > 2. The main goal of this work is to extend this result to H-spaces having more than one non-trivial homotopy group. In order to have an accurate hold on H. Cartan’s result, we... More