Integral Sen theory and integral Hodge filtration

Abstract: We study Nygaard-, conjugate-, and Hodge filtrations on the many variants of Breuil--Kisin modules associated to integral semi-stable Galois representations. This leads to an integral filtered Sen theory, which is closely related to prismatic $F$-crystals and Hodge--Tate crystals. As an application, when the base field is unramified and when considering crystalline representations, we obtain vanishing and torsion bound results on graded of the integral Hodge filtration. Our explicit methods also recover results of Gee--Kisin and Bhatt--Gee--Kisin concerning the mod $p$ Hodge filtration.