ガロアの逆問題特論セミナー


2017/6/6(Tue)

15:00--16:00+ 理D505

Pierre Debes

Univ. Lille 1

Genus zero pull-backs of Galois covers

Pulling back a Galois cover $X\to \P^1$ of group $G$ along a cover $\P^1\to \P^1$ yields ``most of the time'' a new Galois cover of $\P^1$ with the same group. This operation provides a natural tool for Inverse Galois Theory and induces a pre-order on the set of Galois covers. We will present questions that arise from this double perspective, and some answers.