English

On products of harmonic forms

Differential Geometry 2007-05-23 v2 Algebraic Geometry Geometric Topology Symplectic Geometry

Abstract

We prove that manifolds admitting a Riemannian metric for which products of harmonic forms are harmonic satisfy strong topological restrictions, some of which are akin to properties of flat manifolds. Others are more subtle, and are related to symplectic geometry and Seiberg-Witten theory. We also prove that a manifold admits a metric with harmonic forms whose product is not harmonic if and only if it is not a rational homology sphere.

Keywords

Cite

@article{arxiv.math/0004009,
  title  = {On products of harmonic forms},
  author = {D. Kotschick},
  journal= {arXiv preprint arXiv:math/0004009},
  year   = {2007}
}

Comments

Revised to include flatness of formal metrics on tori of arbitrary dimension

R2 v1 2026-07-22T16:32:04.701Z