Let f : R -> R be a continuous function. It is shown that under certain assumptions on f and A : R -> R(+) weak l(1) solutions of the differential inequality - div(A(|del u|)del u) >= f(u) on R(N) are nonnegative. Some extensions of the result in the framework of subelliptic operators on Carnot groups are considered.
机构:
Ankara University, Faculty of Science, Department of Mathematics, 06100 Ankara, TurkeyAnkara University, Faculty of Science, Department of Mathematics, 06100 Ankara, Turkey