English

Three new almost positively curved manifolds

Differential Geometry 2020-08-07 v6

Abstract

A Riemannian manifold is called almost positively curved if the set of points for which all 22-planes have positive sectional curvature is open and dense. We find three new examples of almost positively curved manifolds: Sp(3)/Sp(1)2Sp(3)/Sp(1)^2, and two circle quotients of Sp(3)/Sp(1)2Sp(3)/Sp(1)^2. We also show the quasi-positively curved metric of Tapp [26]} on Sp(n+1)/Sp(n1)Sp(1)Sp(n+1)/Sp(n-1) Sp(1) is not almost positively curved if n3n\geq 3.

Keywords

Cite

@article{arxiv.1504.00255,
  title  = {Three new almost positively curved manifolds},
  author = {Jason DeVito},
  journal= {arXiv preprint arXiv:1504.00255},
  year   = {2020}
}

Comments

Final version. To appear in Geom. Ded

R2 v1 2026-06-22T09:08:04.970Z