arXiv subjects

Khalil Saadi

Publications and source records attributed to Khalil Saadi.

11 recordsLinked to original sources

arXiv2025

Tensorial representations of positive weakly (q,r)-dominated multilinear operators

We introduce and study the class of positive weakly (q,r)-dominated multilinear operators between Banach lattices. This notion extends classical domination and summability concepts to the positive multilinear setting and generates a new positive multi-ideal. A Pietsch domination theorem and a polynomial version are established. Finally, we provide a tensorial representation that yields an isometric identification with the dual of an appropriate completed tensor product.

math.FA↗

arXiv2025

Positive m-homogeneous polynomial ideals

We introduce and study the concept of positive polynomial ideals between Banach lattices. The paper develops the basic principles of these classes and presents methods for constructing positive polynomial ideals from given positive operator ideals. In addition, we provide concrete examples of positive polynomial ideals that illustrate the relevance and significance of these classes.

math.FA↗

arXiv2025

Composition ideals of Lip-Linear operators and a Hilbert space characterization

In this paper, we investigate classes of Lip-linear operators constructed using the composition ideal method. We focus on two fundamental linear operator ideals, $p$-summing and strongly $p$-summing operators, and extend them to define the corresponding classes of Lip-linear operators. Several key results are established, including a characterization theorem for Hilbert spaces originally due to Kwapie\'{n}. Specifically, we show that a Banach space $F$ is isomorphic to a Hilbert space if and only if every factorable strongly $p$-summing Lip-linear operator with values in $F$ is Cohen strongly $p$-summing.

math.FA↗

arXiv2025

Lip-Linear operators and their connection to Lipschitz tensor products

The linear operators defined on the Lipschitz projective tensor product of X and E motivate the study of a distinct class of operators acting on the cartesian produc X E. This class, denoted by LipL(X E;F), combines Lipschitz and linear properties, forming an intermediate framework between bilinear operators and two-Lipschitz operators. We establish an identification between this space and L(X E;F), which also links it to the space of bilinear operators B(AE(X) E;F). Furthermore, we extend summability concepts within this category, with a particular focus on integral and dominated (p;q)-summing operators

math.FA↗

arXiv2024

Positive ideals of multilinear operators

We introduce and explore the concept of positive ideals for both linear and multilinear operators between Banach lattices. This paper delineates the fundamental principles of these new classes and provides techniques for constructing positive multi-ideals from given positive ideals. Furthermore, we present an example of a positive multi-ideal by introducing a new class, referred to as positive (p1,...,pm;r)-dominated multilinear operators. We establish a natural analogue of the Pietsch domination theorem and Kwapien's factorization theorem within this class.

math.FA↗

arXiv2023

New results on MS-Lipschitz summing operators

This paper focuses on the study of MS-Lipschitz p-summing operators, which were initially defined by the authors in 14. Our objective is to establish relationships between T and its linearizations, namely T and T. Additionally, we extend our investigation by introducing a new definition in the category of Lipschitz mappings defined on metric spaces, known as MS-Cohen Lipschitz p-summing. We provide several results and characterizations for this new concept.

math.FA↗

arXiv2017

Further results on strictly Lipschitz summing operators

We give some new characterizations of strictly Lipschitz p-summing operators. These operators have been introduced in order to improve the Lipschitz p-summing operators. Therefore, we adapt this definition for constructing other classes of Lipschitz mappings which are called strictly Lipschitz p-nuclear and strictly Lipschitz (p,r,s)-summing operators. Some interesting properties and factorization results are obtained for these new classes.

math.FA↗

arXiv2017

On the composition ideals of Lipschitz mappings

We study in this paper some property of Lipschitz mappings which admit factorization through an operator ideal. We try to construct Lipschitz cross-norms from known tensor norms in order to represent certain classes of Lipschitz mappings. Inspired by the definition of p-summing linear operators we introduce a new concpet in the the category of Lipschitz mappings that is called strictly Lipschitz p-summing.

math.FA↗

arXiv2017

Cohen factorable p-nuclear multilinear operators

Basing on the work of Pellegrino et al. on factorable strongly p-summing multilinear operators, we will continue study this class of operators and borrowing the same idea for the category of p-nuclear operators. Therefore, we will construct other multilinear and polynomial ideals for which the most valuable results of the theory of p-nuclear linear operators are available, namely the Pietsch domination theorem and the well known factorization given by Cohen and Kwapien for p-nuclear operators.

math.FA↗

arXiv2014

Some properties of Lipschitz strongly p-summing operators

We consider the space of molecules endowed with the transpose version of the Chevet-Saphar norm and we identify its dual space with the space of Lipschitz strongly p-summing operators. We also extend some old results to the category of Lipschitz mappings and we give a factorization result of Lipschitz (p,r,s)-summing operators.

math.FA↗

arXiv2012

Geometric properties of some totally ordered compact sets

In this paper, we show that there are a totally ordered compact K separable (K is Rosenthal compact set), a Hausdorff topology T' on C(K) and two closed subspaces Y1, Y2 of (C(K); Tp) such that (C(K);T') is not universally measurable, (C(K),Tp) = (Y1,Tp) + (Y2,Tp);(Y1,Tp) is isomorphic to (Y2,Tp), (Yj ,Tp) = (Yj,T'), j=1,2; and Bor((C(K)XC(K),T'XT')) is not equal to Bor(C(K)),T'))XC(K)),T')) this is the main result of this work. We start this work to construct totally ordered non metrisable compact sets K(E) from a reference set E which is totally ordered, and from a positive Borel measure on E satisfying some reasonable assumptions.

math.FA↗