| Friday 26 April 2024 | |
| Events for day: Tuesday 12 October 2021 |
| 17:30 - 19:30 Number Theory Webinar Essential Dimension via Prismatic Cohomology School MATHEMATICS Let $f:Y rightarrow X$ be a finite covering map of complex algebraic varieties. The essential dimension of $f$ is the smallest integer $e$ such that, birationally, $f$ arises as the pullback of a covering $Y'rightarrow X'$ of dimension $e$, via a map $X rightarrow X'$. This invariant goes back to classical questions about reducing the number of parameters in a solution to a general $n$-th degree polynomial, and appeared in work of Kronecker and Klein on solutions of the quintic. I will report on joint work with Benson Farb and Jesse Wolfson, where we introduce a new technique, using prismatic cohomology, to obtain lower bounds ... |