A priori estimates of Osserman-Keller type (Q1413596)

The author proves certain pointwise upper bounds in terms of distance to the boundary for subsolutions of certain elliptic equations. The estimates have been proved previously by Osserman and Keller in the case of the equation \(\Delta u = f(u)\) in an open connected set \(\Omega\). The author's assumptions on the regularity of \(f\) in the case of the previous equation are weaker than the ones of Osserman and Keller; moreover the author also considers the case in which the Laplace operator is replaced by a \(p\)-Laplace operator.