On a theorem of M. Cartwright in higher dimensions

Abstract

We consider harmonic functions in the unit ball of ${\mathbb{R}}^{n+1}$ that are unbounded near the boundary but can be estimated from above by some (rapidly increasing) radial weight $w$. Our main result gives some conditions on $w$ that guarantee the estimate from below on the harmonic function by a multiple of this weight. In dimension two this reverse estimate was first obtained by M. Cartwright for the case of the power weights, $w_p(z)=(1-|z|{)}^{-p}$ for $p>1$, and then generalized to a wide class of regular weights by a number of authors.

v.2, 18 pages, added references and acknowledgements, some typos removed