Cohomological obstructions to rational pointsHausdorff Colloquium

by Bjorn Poonen (MIT)

Wednesday Dec 10, 2025, 3:15 PM → 4:45 PM Europe/Berlin

Endenicher Allee 60/1-016 - Lipschitzsaal (Mathezentrum)

Abstract:

It is almost a true statement that the only known way to prove that a variety over a number field has no rational point is to exhibit a cohomological obstruction. I will briefly survey a few things that are known about the Brauer-Manin obstruction, the descent obstruction, and related obstructions.

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