English

Lichnerowicz-Obata Estimate, Almost Parallel $p$-form and Almost Product Manifolds

Differential Geometry 2021-01-07 v5

Abstract

We show a Lichnerowicz-Obata type estimate for the first eigenvalue of the Laplacian of nn-dimensional closed Riemannian manifolds with an almost parallel pp-form (2pn/22\leq p \leq n/2) in L2L^2-sense, and give an almost decomposition result of the manifold under some pinching conditions when 2p<n/22\leq p<n/2.

Keywords

Cite

@article{arxiv.1904.06533,
  title  = {Lichnerowicz-Obata Estimate, Almost Parallel $p$-form and Almost Product Manifolds},
  author = {Masayuki Aino},
  journal= {arXiv preprint arXiv:1904.06533},
  year   = {2021}
}

Comments

66 pages v2:some error corrected, Appendix B added, v3:some error corrected, v4:some proofs simplified, v5: some error corrected, some descriptions simplified

R2 v1 2026-06-23T08:38:38.971Z