Remark on a geometric inequality for closed hypersurfaces in weighted manifolds
Adam Rudnik
TL;DR
This work extends Willmore-type geometric inequalities to noncompact smooth metric measure spaces with nonnegative Bakry-Émery curvature. By leveraging $f$-volume comparison and tubular-volume analysis, it derives two sharp inequalities under $\text{Ric}_f^N\ge0$ and $\text{Ric}_f\ge0$, with equality cases yielding rigid, explicit model geometries: a warped-product exterior in the finite-$N$ case and a twisted-product exterior in the $N=\infty$ case, together with precise forms of the density $f$ outside $\Omega$. The results hinge on the $f$-asymptotic volume ratio $f$-AVR$(g)$ and the assumption of large weighted volume growth $f$-AVR$(g)>0$, connecting boundary geometry to global volume behavior. These findings generalize Willmore-type rigidity from classical nonnegative Ricci curvature to spaces with density and provide nonexistence results for closed $f$-minimal hypersurfaces under positive $f$-AVR. The work thus deepens the interplay between curvature-dimension conditions, boundary geometry, and global volume growth in weighted manifolds, with potential applications to conformal deformations and transport-based geometries.
Abstract
In this paper we consider noncompact smooth metric measure spaces $(M, g,e^{-f}dvol_{g})$ of nonnegative Bakry-Émery Ricci curvature, i.e. $Ric + D^{2}f - \frac{1}{N}df \otimes df \geq 0$, for $0< N \leq \infty$, in order to obtain geometric inequalities for the boundary of a given open and bounded set $Ω\subset M$, with regular boundary $\partial Ω$. Our inequalities are sharp for both the cases $N< \infty$ and $N= \infty$, provided that the underlying ambient space has large weighted volume growth. The rigidity obtained for the $N=\infty$ case holds true precisely when $M \setminus Ω$ is isometric to a twisted product metric and, as such, is a generalization of the Willmore-type inequality for nonnegative Ricci curvature from Agostiniani, Fagagnolo and Mazzieri to the context of weighted manifolds.
