2 papers
math.FA2026
Propagation Phenomena for Operator-Valued Weighted Shifts
Raul E. Curto, Abderrazzak Ech-charyfy, Hamza El Azhar +1
This paper is devoted to the study of propagation phenomena for --hyponormal, quadratically hyponormal, and cubically hyponormal operator-valued weighted shifts. \ First, we sho…
math.FA2023
The Square Root Problem and Subnormal Aluthge Transforms of Recursively Generated Weighted Shifts
Raul E. Curto, Hamza El Azhar, Youssef Omari +1
For recursively generated shifts, we provide definitive answers to two outstanding problems in the theory of unilateral weighted shifts: the Subnormality Problem ({\bf SP}) (relate…