Groups and Operator Algebras Seminar

Speaker: Alain Valette (Université de Neuchâtel)

Title: Maximal Haagerup subgroups in ℤ^2 ⋊ GL_2(ℤ) (after Jiang and Skalski)

Abstract: The Haagerup property (a.k.a a-(T)-menability) is a weak form of amenability. In a countable group, every Haagerup subgroup is contained in a maximal Haagerup subgroup, by Zorn's lemma. The study of maximal Haagerup subgroups of a given group was initiated in 2021 by Y. Jiang and A. Skalski, who classified maximal Haagerup subgroups in ℤ^2 ⋊ GL_2(ℤ). By simplifying the original proof we are able to extend it to more general semi-direct products.

GOA website: https://sites.google.com/view/copenhagen-goa-seminar