On extreme points of the unit ball of a Hardy-Lorentz space

Abstract

We investigate the problem of a characterization of extreme points of the unit ball of a Hardy-Lorentz space $H(\Lambda (\phi ))$, posed by Semenov in 1978. New necessary and sufficient conditions, under which a normalized function $f$ in $H(\Lambda (\phi ))$ belongs to this set, are found. The most complete results are obtained in the case when $f$ is the product of an outer analytic function and a Blaschke factor.

32 pages