My main research interests are combinatorial (and geometric) group theory and large-scale geometry. I am also interested in connections with operator algebras.
I am more specifically working on Baumslag-Solitar groups, the space of finitely generated groups, coarse embeddings in Hilbert and Banach spaces, Haagerup property, Kazdan's property (T), highly transitive actions, and and dense subgroups of some Polish groups.
My Ph.D. Thesis is entitled "Espace des groupes marqués et groupes de Baumslag-Solitar" and was awarded by Université de Neuchâtel (Switzerland). My advisor was Alain Valette. The dissertation is available on the digital library RERO DOC.
N. Louvet, Y. Stalder, and A. Valette, Fonctions conditionnellement de type négatif, représentations irréductibles et propriété (T), L'Enseign. math. 50 (2004), no.34, 239266.
Y. Stalder and A. Valette, Wreath products with the integers, proper actions and Hilbert space compression, Geom. Dedicata, 124 (2007), 199211. (Special issue "Geometric and Probabilistic Methods in Group Theory and Dynamical Systems"). ArXiv version
Y. Stalder, Fixed point properties in the space of marked groups, in "Limits of graphs in group theory and computer science", Proc. Special semester at Centre Bernoulli (Lausanne), Jan-June 2007, G. Arzhantseva and A. Valette editors, Presses Polytechniques et Universitaires Romandes. ArXiv version