High-dimensional limits arising from hyperbolic Poisson k-plane processes
Tillmann Bühler, Daniel Hug, Christoph Thäle
TL;DR
The paper analyzes high-dimensional limits for hyperbolic Poisson $k$-plane processes by examining the total $k$-volume of intersections within a ball and its infinitely divisible limit $Z_{d,k}$. It develops CLT-type criteria via the Lévy measure, aided by beta-function and incomplete beta-function estimates, to delineate when the variance-normalized limit is Gaussian or degenerate as $d\to\infty$ and $k$ grows with $d$. Moreover, it introduces a Lévy-measure rescaling that yields a non-Gaussian limit $\widetilde{Z}^{(b)}$ for fixed codimension $b=d-k$ and a Gaussian limit when $d-k\to\infty$, providing explicit density and cumulant formulas for the limiting non-Gaussian law. These results clarify the subtle high-dimensional behavior of geometric functionals in hyperbolic space, revealing Gaussian limits under certain scalings despite non-Gaussian finite-$d$ limits. The work thus bridges hyperbolic stochastic geometry with the theory of infinitely divisible distributions and offers explicit characterizations of limiting laws via Lévy densities.
Abstract
We consider a stationary Poisson process of $k$-planes in the $d$-dimensional hyperbolic space $\mathbb H^d$ of constant curvature $-1$, with $d \ge 4$ and $1 \le k \le d-1$. It is known that, after centring and normalization, the total $k$-volume of all intersections of $k$-planes with a geodesic ball of radius $R$ converges in distribution, as $R \to \infty$, to a non-Gaussian infinitely divisible random variable $Z_{d,k}$ whenever $2k > d+1$. We investigate the distributional behaviour of $Z_{d,k}$ in the high-dimensional regime $d \to \infty$ and depending on how fast $k$ grows in relation to $d$. We derive precise conditions for the variance normalized sequence to converge in law to a standard Gaussian random variable or to a degenerate law, respectively, and show that an alternative rescaling of the Lévy measures yields an explicit non-Gaussian infinitely divisible limit for fixed codimension $d-k$ and a standard Gaussian limit for $d-k \to \infty$.
