Boundary value problems for elliptic semi-linear equations with measure data

We consider boundary value problems of the form $-(\Delta + V )u + f(u) = \tau$ in $D\subset \mathbb R^N$, $\mathrm{tr}_V u = \nu$ on $\partial D$ where $D$ is a bounded Lipschitz domain in $\mathbb R^N$ and $\mathrm{tr}_V u$ denotes the measure boundary trace associated with $V$. Regarding the non-linear term assume: $f$ is continuous, monotone increasing and $f(0) = 0$. We discuss questions of existence and uniqueness, first in the case $V = 0$ and then for potentials $V$ that blow up at the boundary not faster then $\mathrm{dist}(x; \partial D)^{-2}$.