Square Functions and Variational Estimates for Ritt Operators on $L^1$

Jennifer Hults, Karin Reinhold-Larsson

Let $T$ be a bounded operator. We say $T$ is a Ritt operator if ${\sup }_{n}n\Vert T^n-T^{n+1}\Vert <\infty$. It is know that when $T$ is a positive contraction and a Ritt operator in…