Optimal Hardy-weights for elliptic operators with mixed boundary conditions

Abstract

We construct families of optimal Hardy-weights for a subcritical linear second-order elliptic operator $(P,B)$ with degenerate mixed boundary conditions. By an optimal Hardy-weight for a subcritical operator we mean a nonzero nonnegative weight function $W$ such that $(P-W,B)$ is critical and null-critical with respect to $W$. Our results rely on a recently developed criticality theory for positive solutions of the corresponding mixed boundary value problem.