Renormalized variational principles and Hardy-type inequalities
Résumé
Let $\Omega\subset{\mathbb R}^2$ be a bounded domain on which Hardy's
inequality holds. We prove that $[\exp(u^2)-1]/\delta^2\in
L^1(\Omega)$ if $u\in H^1_0(\Omega)$, where $\delta$ denotes
the distance to $\partial\Omega$. The corresponding higher-dimensional
result is also given.
These results contain both Hardy's and Trudinger's
inequalities, and yield a new variational
characterization of the maximal solution of the Liouville equation
on smooth domains, in terms of a renormalized functional. A global
$H^1$ bound on the difference between the maximal solution and the
first term of its asymptotic expansion follows.