The Levinson conditions mean, roughly speaking, that the trajectories of the degenerate process (or of the dynamical system, in the case of one equation) leave the domain G with probability 1, and that some regularity conditions on the boundary are fulfilled. In this case the degenerate problem (∈ = 0) with boundary conditions preserved on the regular (for the degenerate equation) part of the geometric boundary of the domain, has a unique solution. The solution of the perturbed problem in the Levinson case converges to the unique solution of the degenerate problem as ∈ ↓ 0. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.