1 juli, kl 13.15-15.45, KTH.

kl 13.15-14.15, Yves de Cornulier (Université de Rennes I): on groups embedding quasi-isometrically into Hilbert spaces

Abstract. We conjecture that a finitely generated group embeds quasi-isometrically into a Hilbert space if and only if it is crystallographic. We will give partial results towards this conjecture, based on affine isometric actions of groups. As an outcome, we obtain an original proof of Bourgain's result: a regular tree of degree three does not embed quasi-isometrically into a Hilbert space.