On the operator equation
Author: Constantin Apostol
Journal: Proc. Amer. Math. Soc. 59 (1976), 115-118
MSC: Primary 47A60; Secondary 47B47
MathSciNet review: 0412856
Abstract: A characterization of the operators for which the equation is solvable is given, where is a fixed right invertible operator and is a fixed unilateral shift.