English

On conjugate points and geodesic loops in a complete Riemannian manifold

Differential Geometry 2017-01-18 v2

Abstract

A well-known Lemma in Riemannian geometry by Klingenberg says that if x0x_0 is a minimum point of the distance function d(p,)d(p,\cdot) to pp in the cut locus CpC_p of pp, then either there is a minimal geodesic from pp to x0x_0 along which they are conjugate, or there is a geodesic loop at pp that smoothly goes through x0x_0. In this paper, we prove that: for any point qq and any local minimum point x0x_0 of Fq()=d(p,)+d(q,)F_q(\cdot)=d(p,\cdot)+d(q,\cdot) in CpC_p, either x0x_0 is conjugate to pp along each minimal geodesic connecting them, or there is a geodesic from pp to qq passing through x0x_0. In particular, for any local minimum point x0x_0 of d(p,)d(p,\cdot) in CpC_p, either pp and x0x_0 are conjugate along every minimal geodesic from pp to x0x_0, or there is a geodesic loop at pp that smoothly goes through x0x_0. Earlier results based on injective radius estimate would hold under weaker conditions.

Keywords

Cite

@article{arxiv.1401.5549,
  title  = {On conjugate points and geodesic loops in a complete Riemannian manifold},
  author = {Shicheng Xu},
  journal= {arXiv preprint arXiv:1401.5549},
  year   = {2017}
}