2 papers
math.FA2026
On the Cotlar-Stein lemma
Michael Hartz, Marcel Scherer
We give a direct proof of the Cotlar-Stein lemma, which does not rely on the power trick.
math.CV2025
Inner factors of Dirichlet space functions
Michael Hartz, Stefan Richter
Every function in the Dirichlet space on the unit disc has an inner/outer factorization. We study which inner functions occur in this way. For Blaschke products, this is the well k…