Volume entropy of Hilbert Geometries

Gautier Berck , Andreas Bernig , Constantin Vernicos (1)

1 I3M - Institut de Mathématiques et de Modélisation de Montpellier

It is shown that the volume entropy of a Hilbert geometry associated to an $n$-dimensional convex body of class $C^{1,1}$ equals $n-1$. To achieve this result, a new projective invariant of convex bodies, similar to the centro-affine area, is constructed. In the case $n=2$, and without any assumption on the boundary, it is shown that the entropy is bounded above by $\frac{2}{3-d} \leq 1$, where $d$ is the Minkowski dimension of the extremal set of $K$. An example of a plane Hilbert geometry with entropy strictly between 0 and 1 is constructed.

Domaines: Géométrie différentielle [math.DG]; Géométrie métrique [math.MG]

Gautier Berck, Andreas Bernig, Constantin Vernicos. Volume entropy of Hilbert Geometries. Pacific Journal of Mathematics, 2010, 245, pp.201-225. ⟨10.2140/pjm.2010.245.201⟩. ⟨hal-00819143⟩