English

On $q$-complete and $q$-concave with corners complex manifolds

Complex Variables 2025-10-09 v3

Abstract

It is proved that if there exists a positive and continuous function ff on an nn-dimensional complex manifold XX, qq-convex with corners outside a compact set KXK\subset X and which exhausts XX from below, then dimCHp(X,F)<+dim_{\mathbb{C}}H^{p}(X,{\mathcal{F}})<+\infty for any coherent analytic sheaf F{\mathcal{F}} on XX if p<nqp<n-q. It is known from the theory of Andreotti and Grauert that if a complex space XX is qq-complete, then XX is cohomoloogically qq-complete. Until now it is not known in general if these two conditions are equivalent. The aim of section 44 of this article is to provide a counterexample to the conjecture posed by Andreotti and Grauert ~\cite{ref2} to show that a cohomologically qq-complete space is not necessarily qq-complete. In section 55 of this article, we will prove that there exist for each pair of integers (n,q)(n,q) with 2qn12\leq q\leq n-1 a qq-complete with corners open subset DD of Pn\mathbb{P}^{n} and Fcoh(Pn)\mathcal{F}\in coh(\mathbb{P}^{n}) such that DD is not cohomologically q^\hat{q}-complete with respect to F{\mathcal{F}}. Here q^=n[n1q]\hat{q}=n-[\frac{n-1}{q}], where [x][x] denotes the integral part of xx.

Keywords

Cite

@article{arxiv.0710.3358,
  title  = {On $q$-complete and $q$-concave with corners complex manifolds},
  author = {Youssef Alaoui},
  journal= {arXiv preprint arXiv:0710.3358},
  year   = {2025}
}

Comments

Submitted to Complex Variables and Elliptic Equations

R2 v1 2026-06-21T09:33:15.442Z