Algebra/Topology seminar

Speaker: Frederico Binda (University of Milan)

Title: Revisiting the Hyodo-Kato isomorphism.

Abstract: We use a log variant (based on work of Yao) of the saturated de Rham-Witt complex of Bhatt-Lurie-Mathew to show that the  Hyodo--Kato isomorphism in log crystalline cohomology holds integrally that is, without inverting p, if the base is unramified. As an application, we can use the weight spectral sequence of Mokrane-Nakkajima to build examples of non-trivial torsion classes in the relative (log) de Rham cohomology of a semistable variety over W(k). This is joint work (in progress) with Shuji Saito.