Elliptic problems in domains with degenerate singularities

We consider a model elliptic pseudodifferential equation in Sobolev– Slobodetsky spaces in a reflex angle on the plane. Using the wave factorization, in the case of a unique solution, we study the situation where the aperture of the explementary angle tends to zero. We prove that this limit exists only if the right-hand side satisfies a certain additional condition and obtain this condition using the properties of singular integral operators.