Non-hyperbolic closed geodesics on positively curved Finsler spheres

Huagui Duan

In this paper, we prove that for every Finsler $n$-dimensional sphere $(S^n,F),n\ge 3$ with reversibility $\lambda$ and flag curvature $K$ satisfying ${\left(\frac{\lambda }{1+\lambda }\right)}^2<K\le 1$…