Published online by Cambridge University Press: 03 June 2021
For a smooth strongly convex Minkowski norm $F:\mathbb {R}^n \to \mathbb {R}_{\geq 0}$ , we study isometries of the Hessian metric corresponding to the function $E=\tfrac 12F^2$ . Under the additional assumption that F is invariant with respect to the standard action of $SO(k)\times SO(n-k)$ , we prove a conjecture of Laugwitz stated in 1965. Furthermore, we describe all isometries between such Hessian metrics, and prove Landsberg Unicorn Conjecture for Finsler manifolds of dimension $n\ge 3$ such that at every point the corresponding Minkowski norm has a linear $SO(k)\times SO(n-k)$ -symmetry.
The first author is supported by Beijing Natural Science Foundation (No. Z180004), NSFC (No. 11771331 and No. 11821101), and Capacity Building for Sci-Tech Innovation—Fundamental Scientific Research Funds (No. KM201910028021). The second author thanks DFG for partial support via projects MA 2565/4 and MA 2565/6.