4 citations · 10 across the 15 of their papers we have counts for
15 papers
The Quaternionic Moment Problem
R. Ben Taher, K. Schmüdgen, E. H. Zerouali
In this paper we develop an approach to the full quaternionic moment problem. We define a hierarchy , $k\in \mathbb{N}_…
The Local Operator Moment Problem on
Raul E. Curto, Abderrazzak Ech-charyfy, Hamza El Azhar +1
We study the connections between operator moment sequences of self-adjoint operators on a complex Hilbert space a…
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…
A Combinatorial Formula for Recursive Operator Sequences and Applications
Raul E. Curto, Abderrazzak Ech-charyfy, Kaissar Idrissi +1
We study sequences of bounded operators \((T_n)_{n \ge 0}\) on a complex separable Hilbert space \(\mathcal{H}\) that satisfy a linear recurrence relation of the form $$ T_{n+r} =…
On some properties of -EP and -hypo-EP operators
Rachid Semmami, Hamid Ezzahraoui, El Hassan Zerouali
This article, is devoted to -EP and -hypo-EP operators. We give some characteristic properties of these two classes and various links with other known classes in the literatu…
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…
A Recursive approach to the matrix moment problem
R. Curto, A. Ech-charyfy, K. Idrissi +1
In this paper, we study the truncated matrix moment problem in one variable through recursive matrix extensions. We give necessary and sufficient conditions for a recursive matrix…
Point-Dimension Theory (Part I): The Point-Extended Box Dimension
Nadir Maaroufi, El Hassan Zerouali
This article is an introductory work to a larger research project devoted to pure, applied and philosophical aspects of dimension theory. It concerns a novel approach toward an alt…
Square root problem and Subnormal Aluthge transforms
Hamza El Azhar, Abdelouahab Hanine, Kaissar Idrissi +1
For a non negative measure with atoms, we study the relation between the Square Root Problem of and the problem of subnormality of the Aluthge transform…
Jumping flatness and Aluthge transform of recursive weighted shifts
H. El Azhar, K. Idrissi, E. H. Zerouali
We devote this paper to Hamburger type weighted shifts. We give in particular an affirmative answer to a problem concerning subnormality of the Aluthge transform of Hamburger momen…
On Indecomposable triples associated with nilpotent operators
Ahmed El Khantach, El Hassan Zerouali
We consider in this paper the family of triples where is a finite dimensional space, is a nilpotent linear operator on and is an invariant subspace…
The quintic complex moment problem
Hamza El Azhar, Ayoub Harrat, Kaissar Idrissi +1
Let be a given complex-valued sequence. The truncated complex moment problem (TCMP in short) involves determining necessary and s…
A note on weak positive matrices, finite mass measures and hyponormal weighted shifts
H. El Azhar, K. Idrissi, E. H. Zerouali
We study the class of Hankel matrices for which the -block-matrices are positive semi-definite. We prove that a -block-matrix has non zero determinant if and…
Complex moment problem and recursive relations
Kaissar Idrissi, El Hassan Zerouali
We introduce a new strategy in solving the truncated complex moment problem. To this aim we investigate recursive doubly indexed sequences and their characteristic polynomials. A c…
The Multivariable moment problems and recursive relations
Kaissar Idrissi, El Hassan Zerouali
Let be a -dimensional multisequence. Curto and Fialkow, have shown that if the infinite moment matrix is fini…