Generalized Nearby Cycles via Logarithmic and Relative D-modules
Speaker(s): Lei Wu (Zhejiang University)
Time: 15:00-16:15 October 30, 2025
Venue: Room 77201, Jingchunyuan 78, BICMR
Abstract: Nearby cycles for D-modules along a hypersurface was introduced by Kashiwara and Malgrange by using the so called V-filtrations and by Beilinson-Bernstein by using b-functions in 1980s, which provide a powerful tool in algebraic geometry and representation theory.
In this talk, I will construct (generalized) nearby cycles for regular holonomic D-modules along F, a finite union of hypersurfaces motivated by the method of Beilinson-Bernstein. Then I will give a logarithmic interpretation of Bernstein-Sato ideals of F by using the log structures induced from the graph embedding of F. Finally, I will explain that the relative support of the (generalized) nearby cycles along log stratas are determined by the zeroes of the Bernstein-Sato ideals along the same strata, which generalizes a classic result of Kashiwara and Malgrange.
