Piotr Achinger Title: F-splitting and F-regularity of varieties with a diagonalizable group action Abstract: We will investigate the F-splitting and F-regularity properties of normal varieties in positive characteristic equipped with an effective torus (or more generally diagonalizable group scheme) action. The main result relates invariant F-splittings of such a variety to F-splittings of a suitable quotient log pair. We apply this to study varieties with complexity one torus action, cyclic covers, toric vector bundles, and diagonal splittings. This is joint work with Nathan Ilten and Hendrik Suess.