Le Matematiche  

Douadi Drihem

We present the real interpolation with variable exponent and we prove the basic properties in analogy to the classical real interpolation. More precisely, we prove that under some additional conditions, this method can be reduced to the case of fixed expo... see more

Jean Saint Raymond

Let E be a Banach space and F : E --> E be a 1-Lipschitz set-valued mapping with closed convex non-empty values. We study the set of fixed points Fix(F)={ x in E : x in F(x)} and provide in any space E with dim(E) > 2 an example of such a mapping F ... see more

Patrice Ndambomve, Khalil Ezzinbi

This work concerns the study of the approximate controllability for some nonlinear partial functional integrodifferential equation with infinite delay arising in the modelling of materials with memory, in the framework of Hilbert spaces. We give suff... see more

Carlos Fonseca, Milica Andelic

The aim of this note is to provide a short proof for a recent determinantal formula of generalized Fibonacci numbers.

Sebastiano Pennisi, Tommaso Ruggeri

The aim of this paper is to evaluate the ultra-relativistic limit of a recent causal theory proposed for polyatomic dissipative relativistic gas. The explicitly expression of characteristic velocities of the hyperbolic system is found in term of... see more

Fabio Frigenti

In this paper, we characterize when a quadratic quotient of the Rees algebra, obtained starting with a one-dimensional local ring, has a canonical reduction, generalizing a similar result obtained for Nagata idealization.

Mohamed Ait Mansour, Mohamed Amin Bahraoui, Adham El Bekkali

In this paper, using the concept of completion, we establish the existence of approximate fixed points for contracting set-valued mappings defined in a metric space not necessarily assumed to be complete. As a consequence, we obtain approxi... see more

Maria Flavia Mammana, Biagio Micale

In this paper we extend to cyclical polygons the concepts of maltitude and anti-center of a cyclic quadrilateral and to cyclical polyhedra the concepts of Monge plane and Monge point of a tetrahedron. In addition, we find several properties of these new c... see more

Hüseyin Tuna, Bilender P. Allahverdiev

In this study, we consider the singular discontinuous Sturm-Liouville problem on the whole line with transmission conditions. For this problem the existence of a spectral matrix-valued function is proved. A Parseval equality and an expansion formula are g... see more

Abdolreza Azadi, M. Javad Nikmehr, B. Soleymanzadeh

Let R be a commutative ring with identity, and let Z(R) be the set of zero-divisors of R. Let EG(R) be a simple undirect graph associated with R whose vertex set is the set of all nonzero zero-divisors of R and and two distinct vertices x, ... see more

Yoichi Miyazaki

For the Sobolev space Wmp(Rn) with positive integer m and 1<p<infty, sometimes replaced by 1<=p<infty, we consider the case m-n/p<0 and the case m-n/p=0, and give new proofs of the Sobolev embedding theorems by Muramatu's integral formula. ... see more

Reza Nikandish, M. J. Nikmehr, A. Yassine

In this paper, we introduce the notion of classical n-absorbing submodules of a module M over a commutative ring R with identity, which is a generalization of classical prime submodules. A proper submodule N of M is said to be classical n-absorbing if whe... see more