English

The Jacobian module, the Milnor fiber, and the $D$-module generated by $f^s$

Algebraic Geometry 2016-09-05 v6

Abstract

For a germ ff on a complex manifold XX, we introduce a complex derived from the Liouville form acting on logarithmic differential forms, and give an exactness criterion. We use this Liouville complex to connect properties of the DD-module generated by fsf^s to homological data of the Jacobian ideal; specifically we show that for a large class of germs the annihilator of fsf^s is generated by derivations. Through local cohomology, we connect the cohomology of the Milnor fiber to the Jacobian module via logarithmic differentials. In particular, we consider (not necessarily reduced) hyperplane arrangements: we prove a conjecture of Terao on the annihilator of 1/f1/f; we confirm in many cases a corresponding conjecture on the annihilator of fsf^s but we disprove it in general; we show that the Bernstein--Sato polynomial of an arrangement is not determined by its intersection lattice; we prove that arrangements for which the annihilator of fsf^s is generated by derivations fulfill the Strong Monodromy Conjecture, and that this includes as very special cases all arrangements of Coxeter and of crystallographic type, and all multi-arrangements in dimension 3.

Keywords

Cite

@article{arxiv.1504.07164,
  title  = {The Jacobian module, the Milnor fiber, and the $D$-module generated by $f^s$},
  author = {Uli Walther},
  journal= {arXiv preprint arXiv:1504.07164},
  year   = {2016}
}

Comments

38 pages, 1 figure; typos fixed; references updated