Search results for " Matematica"

Common fixed points in ordered Banach spaces

2008

In this paper we introduce the notion of g-weak isotone mappings in an ordered Banach space and we extend some common fixed point theorems of Dhage, O’Regan and Agarwal

AN OPTIMIZATION THEOREM IN SPACES ADMITTING A CONTINUOUS BIJECTION ONTO [0,1]

2011

A note on *-derivations of partial *-algebras

2012

A definition of *-derivation of partial *-algebra through a sufficient family of ips-forms is proposed.

Monotone generalized nonlinear contractions and fixed point theorems in ordered metric spaces

2011

The purpose of this paper is to present some fixed point theorems for T -weakly isotone increasing mappings which satisfy a generalized nonlinear contractive condition in complete ordered metric spaces. As application, we establish an existence theorem for a solution of some integral equations.

FORMAZIONE DI PATTERN PER IL PROCESSO DELL'ELETTRODEPOSIZIONE IN MODELLI DI TIPO REAZIONE-DIFFUSIONE

2014

Permutations of zero-sumsets in a finite vector space

2020

Abstract In this paper, we consider a finite-dimensional vector space 𝒫 {{\mathcal{P}}} over the Galois field GF ⁡ ( p ) {\operatorname{GF}(p)} , with p being an odd prime, and the family ℬ k x {{\mathcal{B}}_{k}^{x}} of all k-sets of elements of 𝒫 {\mathcal{P}} summing up to a given element x. The main result of the paper is the characterization, for x = 0 {x=0} , of the permutations of 𝒫 {\mathcal{P}} inducing permutations of ℬ k 0 {{\mathcal{B}}_{k}^{0}} as the invertible linear mappings of the vector space 𝒫 {\mathcal{P}} if p does not divide k, and as the invertible affinities of the affine space 𝒫 {\mathcal{P}} if p divides k. The same question is answered also in the case where …

Dependence of effective properties upon regular perturbations

2022

In this survey, we present some results on the behavior of effective properties in presence of perturbations of the geometric and physical parameters. We first consider the case of a Newtonian fluid flowing at low Reynolds numbers around a periodic array of cylinders. We show the results of [43], where it is proven that the average longitudinal flow depends real analytically upon perturbations of the periodicity structure and the cross section of the cylinders. Next, we turn to the effective conductivity of a periodic two-phase composite with ideal contact at the interface. The composite is obtained by introducing a periodic set of inclusions into an infinite homogeneous matrix made of a di…

PLS...su e giù per l'Italia

2012

Thermal Energy Density Driven Magnetic Reconnection

Magnetic reconnection is usually associated with conversion of magnetic energy into particle acceleration or thermal energy. However, a specific reconnection process driven by plasma pressure gradients was identified in Ref.[1] with a consistent theory of (non-ideal) MHD m0=1 modes in well confined plasmas. This process, based on an Ohm's law contribution to the electron balance equations, remains the basis for the explanation of the observed sawtooth oscillations of the central plasma pressure and for the inferred magnetic field structures due to fishbone oscillations associated with injected high energy particle populations. A novel process [2] expected to have a wide range of application…

Non-Thermal Fusion Burning Plasma Regimes

The Ignitor project is aimed at approaching ignition conditions in Deuterium-Tritium plasmas in order to investigate the issues related to the kind of characteristics of these plasmas, following the line of compact high field opened with the Alcator and Frascati Torus programs, which were capable of producing high density plasma regimes with record confinement properties combined with high degrees of plasma purity. We present a theoretical model describing the emergence of tridimensional structures in magnetically confined plasmas which can significantly change the conditions under which meaningful fusion burn conditions can be reached. These structures can be said to consist of "captive ba…