Time：14:00-16:00, Wednesday, December 3 2025
Venue：E4-233
Speaker：Alexandre Lourdeaux, Southern University of Science and Technology
Title：Brauer invariants of linear algebraic groups
Abstract: Our talk deals with the cohomological invariants of smooth and connected linear algebraic groups over an arbitrary field. The notion of cohomological invariants was formalized by Serre in the 90's. It enables to study via Galois cohomology the geometry of linear algebraic groups or forms of algebraic stuctures (such as central simple algebras with involution).
We intend to introduce the general ideas of the theory and to present a generalization of a result by Blinstein and Merkurjev on degree 2 invariants with coefficients Q/Z(1), that is invariants taking values in the Brauer group. More precisely our result gives a description of these invariants for every smooth and connected linear groups, in particular for non reductive groups over an imperfect field (as pseudo-reductive or unipotent groups for instance)
