New Lower Bounds for Optimal Horoball Packing Density in Hyperbolic $n$-space for $6\le n\le 9$

Robert T. Kozma, Jenő Szirmai

Koszul type Coxeter simplex tilings exist in hyperbolic $n$-space ${\mathbb{H}}^n$ up to $n=9$, and their horoball packings achieve the highest known regular ball packing densitie…