In this paper, we study some nonlinear elliptic equations on a compact
-dimensional
weighted Riemannian manifold of positive
-Bakry–Émery–Ricci
curvature and convex boundary. Our main purpose is to find conditions which imply
that such elliptic equations admit only constant solutions. As an application, we
obtain weighted Sobolev inequalities with explicit constants that extend the
inequalities obtained by Ilias [1983; 1996] in the Riemannian setting. In a last part of
the article, as applications we derive a new Onofri inequality, a logarithmic Sobolev
inequality and estimates for the eigenvalues of a weighted Laplacian and for the trace
of the weighted heat kernel.