ISSN: 1314-3344
GAO Yanmin and GAO Hongya
We consider boundary value problem of the form    Pn i=1 Di(ai(x, Du(x))) = f, x ∈ â¦, u(x) = u∗(x), x ∈ ∂â¦. We show that regularity of boundary datum u∗ forces u to have regularity as well. A similar result is obtained for obstacle problem.