# Stefan Reppen: A brief introduction to the Hodge, Tate and Mumford-Tate conjectures

**Time: **
Fri 2019-10-18 13.00 - 14.00

**Location: **
Sal 31, hus 5, Kräftriket

**Participating: **
Stefan Reppen, SU

### Abstract

Both the Hodge and the Tate conjecture concern the algebraicity of certain cohomology classes invariant under certain group actions (the Mumford-Tate group respectively the Galois group). The Mumford-Tate conjecture is (somewhat of) a bridge between the other two. In this talk we briefly present the three conjectures and state some known results. If there is time we give a presentation of a motivic version of the conjectures.