On the Hodge and V-filtrations of mixed Hodge modules

Abstract: In this note, we prove a filtered version of Beilinson-type formula for the V-filtration of Kashiwara and Malgrange for any D-module underlying a complex mixed Hodge module along a hypersurface, using Hodge filtrations on the localization. We give some applications to the theory of higher multiplier and Hodge ideals. The main result is that the higher multiplier ideals can be deduced directly from the Hodge ideals by taking a suitable limit. As a corollary, we conclude that the Hodge ideals are left semi-continuous if and only if they coincide with the higher multiplier ideals. In an appendix, we make some general observations about Hodge and higher multiplier ideals. We observe that results of Saito and Chen-Musta\c{t}\u{a} give a birational formula for higher multiplier ideals, answering a question of Schnell and the second author, and that the Kodaira vanishing theorem for twisted Hodge modules gives a short proof of the vanishing theorem for Hodge ideals, strengthening a result of B. Chen.