Date

Ober­sem­in­ar "Num­ber The­ory and Arith­met­ic­al Stat­ist­ics": Ju­li­an De­meio (Han­nov­er), The Grun­wald Prob­lem for solv­able groups

Location: D2 314
Organizer: Prof. Dr. Jürgen Klüners

Title: The Grunwald Problem for solvable groups

Abstract: Let $K$ be a number field. The Grunwald problem for a finite group (scheme) G/K asks what is the closure of the image of $H^1(K,G) \to \prod_{v \in M_K} H^1(K_v,G)$. For a general $G$, there is a Brauer—Manin obstruction to the problem, and this is conjectured to be the only one. In 2017, Harpaz and Wittenberg introduced a technique that managed to give a positive answer (BMO is the only one) for supersolvable groups. I will present a new fibration theorem over quasi-trivial tori that, combined with the approach of Harpaz and Wittenberg, gives a positive answer for all solvable groups.