Gâteaux derivative and orthogonality in -classes.
Generalizations of Kaplansky's Theorem Involving Unbounded Linear Operators
We are mainly concerned with the result of Kaplansky on the composition of two normal operators in the case in which at least one of the operators is unbounded.
Generalizations of the results on powers of -hyponormal operators.
Generalized derivation modulo the ideal of all compact operators.
Generalizing normality for operators on Banach spaces: Hyponormality. I.