$(p, q)$-Sobolev inequality and Nash inequality on forward complete Finsler metric measure manifolds
Xinyue Cheng, Qihui Ni
TL;DR
This work extends Sobolev and Nash-type inequalities to forward complete Finsler metric measure manifolds under a lower bound on the infinite Ricci curvature ${\rm Ric}_{\infty} \ge -K$. The authors first derive a global $p$-Poincaré inequality using volume doubling and covering arguments, then obtain a global $(p,q)$-Sobolev inequality via Xia's linearization technique, followed by a Nash inequality as an application of the Poincaré bound and volume comparison. The results provide explicit dependence of constants on geometric data such as the reversibility $\Lambda$, diameter, total measure, and distortion, thereby enabling large-scale analysis on irreversible Finsler spaces with curvature bounds. Overall, the paper broadens the functional-analytic toolkit available for Finsler geometry, offering global, optimal-type inequalities that parallel classical Riemannian results in a non-reversible setting.
Abstract
In this paper, we carry out in-depth research centering around the $(p, q)$-Sobolev inequality and Nash inequality on forward complete Finsler metric measure manifolds under the condition that ${\rm Ric}_{\infty} \geq -K$ for some $K \geq 0$. We first obtain a global $p$-Poincaré inequality on such Finsler manifolds. Based on this, we can derive a $(p, q)$-Sobolev inequality. Furthermore, we establish a global optimal $(p, q)$-Sobolev inequality with a sharp Sobolev constant. Finally, as an application of the $p$-Poincaré inequality, we prove a Nash inequality.
