Doubling and Poincar\'e inequalities for uniformized measures on Gromov hyperbolic spaces

Abstract

We generalize the recent results of Bj\"orn-Bj\"orn-Shanmugalingam \cite{BBS20} concerning how measures transform under the uniformization procedure of Bonk-Heinonen-Koskela for Gromov hyperbolic spaces \cite{BHK} by showing that these results also hold in the setting of uniformizing Gromov hyperbolic spaces by Busemann functions that we introduced in \cite{Bu20}. In particular uniformly local doubling and uniformly local Poincar\'e inequalities for the starting measure transform into global doubling and global Poincar\'e inequalities for the uniformized measure. We then show in the setting of uniformizations of universal covers of closed negatively curved Riemannian manifolds equipped with the Riemannian measure that one can obtain sharp ranges of exponents for the uniformized measure to be doubling and satisfy a $1$-Poincar\'e inequality. Lastly we introduce the procedure of uniform inversion for uniform metric spaces, and show that both the doubling property and the $p$-Poincar\'e inequality are preserved by uniform inversion for any $p \geq 1$.