A Singular Boundary Value Problem for Uniformly Elliptic Operators

Strong solvability in the Sobolev space W 2 p is proved for the oblique derivative problem n j i=1 aij x Diju = f x almost everywhere in ∂u/∂ + σ x u = ϕ x in the trace sense on ∂ in the case when the vector field x has a contact of infinite order with ∂ at the points of some non-empty subset E ⊂ ∂ .