Search results for "MATEMATICA"
showing 10 items of 1637 documents
Differential structure associated to axiomatic Sobolev spaces
2020
The aim of this note is to explain in which sense an axiomatic Sobolev space over a general metric measure space (à la Gol’dshtein–Troyanov) induces – under suitable locality assumptions – a first-order differential structure. peerReviewed
Coupled coincidence point results for (φ,ψ)-contractive mappings in partially ordered metric spaces
2014
Abstract. In this paper, we extend the coupled coincidence point theorems for a mixed g-monotone operator F : X × X → X $F:X\times X\rightarrow X$ obtained by Alotaibi and Alsulami [Fixed Point Theory Appl. (2011), article ID 44], by weakening the involved contractive condition. Two examples are given to illustrate the effectiveness of our generalizations. Our result also generalizes some recent results announced in the literature. Moreover, some applications to integral equations are presented.
Coupled fixed-point results for T-contractions on cone metric spaces with applications
2015
The notion of coupled fixed point was introduced in 2006 by Bhaskar and Lakshmikantham. On the other hand, Filipovićet al. [M. Filipovićet al., “Remarks on “Cone metric spaces and fixed-point theorems of T-Kannan and T-Chatterjea contractive mappings”,” Math. Comput. Modelling 54, 1467–1472 (2011)] proved several fixed and periodic point theorems for solid cones on cone metric spaces. In this paper we prove some coupled fixed-point theorems for certain T-contractions and study the existence of solutions of a system of nonlinear integral equations using the results of our work. The results of this paper extend and generalize well-known comparable results in the literature.
Coupled fixed point theorems for symmetric (phi,psi)-weakly contractive mappings in ordered partial metric spaces
2013
We establish some coupled fixed point theorems for symmetric (phi,chi)-weakly contractive mappings in ordered partial metric spaces. Some recent results of Berinde (Nonlinear Anal. 74 (2011), 7347-7355; Nonlinear Anal. 75 (2012), 3218-3228) and many others are extended and generalized to the class of ordered partial metric spaces.
Multiple solutions for semilinear Robin problems with superlinear reaction and no symmetries
2021
We study a semilinear Robin problem driven by the Laplacian with a parametric superlinear reaction. Using variational tools from the critical point theory with truncation and comparison techniques, critical groups and flow invariance arguments, we show the existence of seven nontrivial smooth solutions, all with sign information and ordered.
Existence of three solutions for a mixed boundary value system with (p_1,...,p_m)-Laplacian
2014
In this paper we prove the existence of at least three weak solutions for a mixed boundary value system with (p_1,,...,p_m)-Laplacian. The approach is based on variational methods.
$PT$-symmetric graphene under a magnetic field
2016
We propose a $PT$-symmetrically deformed version of the graphene tight-binding model under a magnetic field. We analyze the structure of the spectra and the eigenvectors of the Hamiltonians around the $K$ and $K'$ points, both in the $PT$-symmetric and $PT$-broken regions. In particular we show that the presence of the deformation parameter $V$ produces several interesting consequences, including the asymmetry of the zero-energy states of the Hamiltonians and the breakdown of the completeness of the eigenvector sets. We also discuss the biorthogonality of the eigenvectors, which {turns out to be} different in the $PT$-symmetric and $PT$-broken regions.
A version of Hake’s theorem for Kurzweil–Henstock integral in terms of variational measure
2019
Abstract We introduce the notion of variational measure with respect to a derivation basis in a topological measure space and consider a Kurzweil–Henstock-type integral related to this basis. We prove a version of Hake’s theorem in terms of a variational measure.
Un’esperienza educativa di trasposizione culturale nella scuola primaria
2015
La nostra ricerca vuole mostrare come lo studio di approcci sviluppati in diversi contesti culturali può essere importante per riflettere sulle nostre pratiche didattiche e per progettare nuove sperimentazioni nelle classi. In particolare abbiamo studiato le rappresentazioni grafiche usate per descrivere e risolvere problemi additivi nella scuola primaria in Russia e Cina. In questo articolo introdurremo l’idea di trasposizione culturale che sarà anche esemplificata attraverso la descrizione e analisi di due percorsi didattici realizzati in una II e in una V primaria italiane.