ON A DEGENERATING PROBLEM WITH DIRECTIONAL DERIVATIVE
Vladimir G. Maz’ja · Mathematics of the USSR-Sbornik · 1972
We study a problem with directional derivative for a second order elliptic equation. We assume that smooth compact submanifolds have been selected from the boundary , and that the vector field is tangent to () at points of and not tangent to . We show that the problem has a unique solution, obtain estimates of the solutions in (), and prove that the inverse operator is compact.Bibliography: 29 items.