Singular large diffusivity and spatial homogenization in a non homogeneous linear parabolic problem

We make precise the sense in which spatial homogenization to a constant function in space is attained in a linear parabolic problem when large diffusion in all parts of the domain is assumed. Also interaction between diffusion and boundary flux terms is considered. Our starting point is a detailed analysis of the large diffusion effects on the associated elliptic and eigenvalue problems. Here convergence is shown in the energy space H-1(Omega) and in the space of continuous functions C(Omega). In the parabolic case we prove convergence in the functional space L-infinity((0, T), L-2(Omega)) boolean AND L-2((0, T), H-1(Omega))