English

Expected local topology of random complex submanifolds

Algebraic Geometry 2022-02-23 v2

Abstract

Let n2n\geq 2 and r{1,,n1}r\in \{1, \cdots, n-1\} be integers, MM be a compact smooth K\''ahler manifold of complex dimension nn, EE be a holomorphic vector bundle with complex rank rr and equipped with an hermitian metric hEh_E, and LL be an ample holomorphic line bundle over MM equipped with a metric hh with positive curvature form. For any dNd\in \mathbb{N} large enough, we endorse the space of holomorphic sections H0(M,ELd)H^0(M,E\otimes L^d) with the natural Gaussian measure associated to hEh_E , hh and its curvature form. Let UMU\subset M be an open subset with smooth boundary. We prove that the average of the (nr)(n-r)-th Betti number of the vanishing locus in UU of a random section ss of H0(M,ELd)H^0(M,E\otimes L^d) is asymptotic to (n1r1)dnUc1(L)n{n-1 \choose r-1} d^n\int_U c_1(L)^n for large dd. On the other hand, the average of the other Betti numbers are o(dn)o(d^n). The first asymptotic recovers the classical deterministic global algebraic computation. Moreover, such a discrepancy in the order of growth of these averages is new and constrasts with all known other smooth Gaussian models, in particular the real algebraic one. We prove a similar result for the affine complex Bargmann-Fock model.

Keywords

Cite

@article{arxiv.2202.10247,
  title  = {Expected local topology of random complex submanifolds},
  author = {Damien Gayet},
  journal= {arXiv preprint arXiv:2202.10247},
  year   = {2022}
}
R2 v1 2026-06-24T09:47:51.243Z