English

A Zoll counterexample to a geodesic length conjecture

Differential Geometry 2014-10-03 v2 Functional Analysis Metric Geometry

Abstract

We construct a counterexample to a conjectured inequality L<2D, relating the diameter D and the least length L of a nontrivial closed geodesic, for a Riemannian metric on the 2-sphere. The construction relies on Guillemin's theorem concerning the existence of Zoll surfaces integrating an arbitrary infinitesimal odd deformation of the round metric. Thus the round metric is not optimal for the ratio L/D.

Keywords

Cite

@article{arxiv.0711.1229,
  title  = {A Zoll counterexample to a geodesic length conjecture},
  author = {Florent Balacheff and Christopher Croke and Mikhail G. Katz},
  journal= {arXiv preprint arXiv:0711.1229},
  year   = {2014}
}

Comments

10 pages; to appear in Geometric and Functional Analysis

R2 v1 2026-06-21T09:41:13.706Z