Speaker: Joseph Ayoub Date: 10:30 05/02/2021 Title: A new Weil cohomology in characteristic $p$ and a ring of $p$-adic periods Abstract: By a rather straightforward analogy with the case of complex numbers, one can define a Kontsevich--Zagier type algebra of $p$-adic periods. These are essentially integrals of algebraic $p$-adically convergent power series over a $p$-adic cube. For sometimes, it was unclear what was the `meaning' of this ring of $p$-adic periods. In this talk, I will explain how this ring appears naturally as the ring of coefficients of a new Weil cohomology defined on varieties over the finite field with $p$ elements.