13 citations · 13 across the 10 of their papers we have counts for
12 papers
Harnack parts for 5-by-5 truncated shift with numerical radius one
Mohammed Benharrat
We provide a complete description of the Harnack part for normalized truncated shift of size five with numerical radius one. We prove that any operator in this Harnack component mu…
Some Sharp bounds for the generalized Davis-Wielandt radius
Mehdi Naimi, Mohammed Benharrat, Faouzi Hireche
This paper presents a study of the generalized Davis-Wielandt radius of Hilbert space operators. New lower bounds for the generalized Davis-Wielandt radius and numerical radius are…
Fractional powers approach of maximal accretive operators for a class of third order abstract Cauchy problems
Mohammed Benharrat, Flank D. M. Bezerra
In this paper we explore the theory of fractional powers of maximal accretive operators to obtain results of existence, regularity and behavior asymptotic of solutions for linear a…
The Moore-Penrose inverse of accretive operators with application to quadratic operator pencils
Fairouz Bouchelaghem, Mohammed Benharrat
We establish some relationships between an m-accretive operator and its Moore-Penorse inverse. We derive some perturbation result of the Moore-Penorse inverse of a maximal accretiv…
On the circular numerical range of 5-by-5 partial isometries
Mehdi Naimi, Mohammed Benharrat
We prove, in some cases in term of kippenhahn curve, that if 5-by-5 partial isometry whose numerical range is a circular disc then its center is must be the origin. This gives a pa…
A factorization of a quadratic pencils of accretive operators and applications
F. Bouchelaghem, M. Benharrat
A canonical factorization is given for a quadratic pencil of accretive operators in a Hilbert space. Also, we establish some relationships between an m-accretive operator and its M…
A perturbation result of m-accretive linear operators in Hilbert spaces
Mohammed Benharrat
A new sufficient condition is given for the sum of linear m-accretive operator and accretive operator one in a Hilbert space to be m-accretive. As an application, an extended resul…
Harnack parts for some truncated shifts
Gilles Cassier, Mohammed Benharrat
The purpose of this paper is to analysis the Harnack part of some truncated shifts whose -numerical radius equal one in the finite dimensional case. As pointed out in Theorem 1.…
Right and left quotient of two bounded operators on Hilbert spaces
Mohammed Benharrat
We define a left quotient as well as a right quotient of two bounded operators between Hilbert spaces, and we parametrize these two concepts using the Moore-Penrose inverse. In par…
HARNACK parts of -Contractions
Gilles Cassier, Mohammed Benharrat, Soumia Belmouhoub
The purpose of this paper is to describe the Harnack parts for the operators of class C ( \textgreater{} 0) on Hilbert spaces which were introduced by B. Sz. Nagy and C. Foi…
Left and right generalized Drazin invertible operators and Local spectral theory
Mohammed Benharrat, Kouider Miloud Hocine, Bekkai Messirdi
In this paper, we give some characterizations of the left and right generalized Drazin invertible bounded operators in Banach spaces by means of the single-valued extension propert…
Optimal control with time-delays via the penalty method
Mohammed Benharrat, Delfim F. M. Torres
We prove necessary optimality conditions of Euler-Lagrange type for a problem of the calculus of variations with time delays, where the delay in the unknown function is different f…