On functoriality of Baum-Bott residues

Abstract

We prove a functoriality formula for Baum--Bott residues under holomorphic pull-back. Let $f:V\to X$ be a holomorphic map generically transverse to a singular holomorphic foliation $\mathcal{F}$ on $X$. Under a compatibility condition on the tangent and normal sheaves, the localized Baum--Bott class of $f^{\ast }\mathcal{F}$ is the pull-back of that of $\mathcal{F}$, and the corresponding residue is obtained by localized intersection. We also discuss the universal relative class of Baum and Bott and its relation with the rationality conjecture. If the characteristic polynomial has rational coefficients, rational residues remain rational under the pull-backs considered here. For proper surjective generically finite maps of equal dimension, we obtain in addition a push-forward formula; hence rationality is equivalent before and after pull-back, in particular for bimeromorphic modifications satisfying the hypotheses of the theorem.

arXiv commentRevised version. The paper now focuses on the functoriality of Baum-Bott residues, its applications, and its universal interpretation. We thank Javier Acea, Olivier Thom, and Alan Muniz for pointing out a subtlety concerning transverse discs. Related applications will be treated in future work