Nicolas Mascot (TCD)

will speak on

Hensel-lifiting torsion points on Jacobians, and computation of Galois representations from higher étale cohomology

Time: 12:00PM
Date: Fri 21st February 2020
Location: Seminar Room SCN 1.25 [map]

Further information

Abstract: (Note the unusual day and time)

We will describe an algorithm to p-adically lift torsion points on Jacobians of curves. As an application, we will show how to compute explicitly mod l Galois representations occurring in the Jacobians of curves, and also more generally in higher etale cohomology spaces of higher-dimensional varieties. This has many applications, ranging from exploring Langlands's program to point counting in cryptography.


Although the topic may sound abstract, this talk will be very introductory, and will include several concrete examples; for instance, we will apply these techniques to a Galois representation found in the degree 2 etale cohomology of a surface and attached to a modular form of exotic type.

(This talk is part of the Algebra and Number Theory series.)

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