Yi-Yun Gao

Extreme points of the unit balls and isometries of noncommutative quasi-Banach Marcinkiewicz spaces

We characterize extreme points of the (positive) unit balls of Marcinkiewicz spaces with respect to their natural quasi-norms. Having these results at hand, we show that every positive surjective isometry on a noncommutative Marcinkiewicz space is of elementary form. In particular, a linear mapping on a noncommutative...