Article
Keywords:
Moser iteration; singular perturbation; large coupling limit
Summary:
We consider heat semigroups of the form $\exp (t(\Delta - \lambda {\bf 1}_{\Omega _0}))$ on bounded domains. These singularly perturbed equations arise in certain models of diffusion limited chemical reactions. Using variants of Moser's iteration scheme, we show sub-exponential decay in the strong coupling limit, i.e., as $\lambda \nearrow \infty $, in compact subdomains of the ``obstacle'', $\Omega _0$.