Stability of closed characteristics on compact hypersurfaces in ${\mathbb{R}}^{2n}$ under pinching condition

In this article, let $\mathrm{\Sigma }\subset {\mathbb{R}}^{2n}$ be a compact convex hypersurface which is $(r,R)$-pinched with $\frac{R}{r}<\sqrt{3\mathrm{/}2}$. Then $\text{Sg}$ carries at least two strictly elliptic closed characteristics; moreover, $\text{Sg}$ carries at least $2[\frac{n+2}{4}]$ non-hyperbolic closed characteristics.