English

Pseudoconvex submanifolds in Kahler 4-manifolds

Differential Geometry 2022-08-02 v1

Abstract

On Kahler 4-manifolds, not necessarily compact or of finite topological type, we obtain relationships between the fundamental group of compact embedded Levi-flat or pseudoconvex submanifold and the fundamental group of the ambient manifold M4M^4. When a Levi-flat submanifold V3V^3 has finite fundamental group then π1(M4)=ιπ1(V3)\pi_1(M^4)=\iota_*\pi_1(V^3); when a non-separating pseudoconvex submanifold V3V^3 has finite fundamental group, then π1(M4)=ιπ1(V3)Z\pi_1(M^4)=\iota_*\pi_1(V^3)\rtimes\mathbb{Z}. As applications, if a Kahler manifold (compact or not) has an embedded holomorphic P1\mathbb{P}^1 of positive self-intersection, it must intersect all other holomorphic P1P^1 of non-negative self-intersection, the fundamental group of M4M^4 is trivial, and no ALE or ALF ends exist. If a Levi-flat submanifold and an embedded holomorphic P1\mathbb{P}^1 of positive self-intersection both exist, they intersect. The total number of ALE plus ALF ends is zero or one regardless of what other kinds of ends exist. We provide examples, such as a 2-ended scalar-flat Kahler metric conformal to the Taub-NUT.

Keywords

Cite

@article{arxiv.2208.00975,
  title  = {Pseudoconvex submanifolds in Kahler 4-manifolds},
  author = {Brian Weber},
  journal= {arXiv preprint arXiv:2208.00975},
  year   = {2022}
}