English

Closed $\mathrm{G}_2$ structures on compact manifolds satisfying the known topological obstructions to holonomy $\mathrm{G}_2$ metrics

Differential Geometry 2025-08-19 v1

Abstract

We construct new compact manifolds endowed with closed G2\mathrm{G}_2 structures that satisfy the topological properties found by Joyce and Baraglia for the existence of a torsion-free G2\mathrm{G}_2 structure in the same cohomology class. Those manifolds arise as resolutions of orbifolds of the form M/Z2M/\mathbb{Z}_2, where MM itself does not admit any torsion-free G2\mathrm{G}_2 structure. We develop an equivariant resolution procedure for closed G2\mathrm{G}_2 orbifolds with Z2\mathbb{Z}_2 isotropy, and analyze some topological properties of the resolved manifolds, including their first Pontryagin class and certain triple Massey products.

Keywords

Cite

@article{arxiv.2508.12658,
  title  = {Closed $\mathrm{G}_2$ structures on compact manifolds satisfying the known topological obstructions to holonomy $\mathrm{G}_2$ metrics},
  author = {Lucía Martín-Merchán},
  journal= {arXiv preprint arXiv:2508.12658},
  year   = {2025}
}

Comments

50 pages. Comments welcome!