Agmon estimates for the difference of exact and approximate Dirichlet eigenfunctions for difference operators

We analyze a general class of difference operators <tex>H_\varepsilon = T_\varepsilon + V_\varepsilon</tex> on <tex>\ell^2(\varepsilon \mathbb{Z}^d</tex>), where <tex>V_\varepsilon</tex> is a multi-well
potential and <tex>\varepsilon</tex> is a small parameter. We  construct approximate eigenfunctions in
neighbourhoods of the different wells and give weighted <tex>\ell^2</tex>-estimates for the difference of these
and the exact eigenfunctions of the associated Dirichlet-operators.