17 citations · 64 across the 32 of their papers we have counts for
6 papers · 1 filter
A Contribution to the Fong-Tsui Conjecture Related to Self-adjoint Operators
Mohammed Hichem Mortad
We are interested in an open question raised by Fong-Tsui (dating back to the beginning of the eighties of last century) as to whether a bounded operator whose absolute value is le…
Exponentials of Bounded Normal Operators
Aicha Chaban, Mohammed Hichem Mortad
The present paper is mainly concerned with equations involving exponentials of bounded normal operators. Conditions implying commutativity of those normal operators are given. This…
Exponentials of Normal Operators and Commutativity of Operators: A New Approach
Mohammed Hichem Mortad
We present a new approach to the question of when the commutativity of operator exponentials implies that of the operators. This is proved in the setting of bounded normal operator…
The Sum of Two Unbounded Linear Operators: Closedness, Self-adjointness and Normality
Mohammed Hichem Mortad
In the present paper we give results on the closedness and the self-adjointness of the sum of two unbounded operators. We present a new approach to these fundamental questions in o…
Products of Unbounded Normal Operators
Mohammed Hichem Mortad
The present paper partly constitutes an "unbounded" follow-up of a paper by I. Kaplansky dealing with bounded products of normal operators. Results on the normality of unbounded pr…
More on the Normality of the Unbounded Product of Two Normal Operators
Mohammed Hichem Mortad, Khaldia Madani
Let and be two -non necessarily bounded- normal operators. We give new conditions making their product normal. We also generalize a result by Deutsch et al on normal produc…