The boundary value problem Lu=f(vertical bar u vertical bar) in Omega,
u vertical bar partial derivative Omega = w, is studied, where Omega
is an arbitrary, possibly unbounded, open subset of Rn, L = Sigma(i)(n
), j=1 partial derivative/partial derivative x(j)(a(ij)(x)partial deri
vative/partial derivative x(j)) is a differential operator of elliptic
type with measurable coefficients, and w, f are some functions.