The boundary Harnack principle for the fractional Laplacian
Tom 123 / 1997
Studia Mathematica 123 (1997), 43-80
DOI: 10.4064/sm-123-1-43-80
Streszczenie
We study nonnegative functions which are harmonic on a Lipschitz domain with respect to symmetric stable processes. We prove that if two such functions vanish continuously outside the domain near a part of its boundary, then their ratio is bounded near this part of the boundary.