Solvability of boundary value problems for second-order elliptic differential-operator equations with a spectral parameter and with a discontinuous coefficient at the highest derivative

Abstract

In a Hilbert space H, we study the solvability of boundary value problems for second-order elliptic differential-operator equations with a spectral parameter and with a discontinuous (piecewise constant) coefficient at the highest derivative. At the point of discontinuity, we find a transmission condition, which contains a linear unbounded operator. We present an application of the results to elliptic boundary value problems.