From arcs in surfaces to algebraic arcs : a mapping class group proof of homological stability for symplectic groups.

by Nathalie Wahl (University of Copenhagen))

Friday 6 Nov 2026, 11:00 → 12:00 Europe/Brussels

B/2nd floor-B.203 - Seminar room (Marc de Hemptinne (chemin du Cyclotron, 2, Louvain-la-Neuve))

I will explain my joint work with Ismael Sierra, where we define a notion of « algebraic arcs » in R-modules equipped with an alternating form, and use them to improve the known range for homological stability of symplectic groups over quite general rings, by mimicking a proof for mapping class groups of surfaces.