Search results for "Analisi Matematica"

Henstock type integral in compact zero-dimensional metric space and quasi-measures representations

2012

Properties of a Henstock type integral defined on a compact zero-dimensional metric space are studied. Theorems on integral representation of so-called quasi-measures, i.e., linear functionals on the space of “polynomials” defined on the space of the above mentioned type, are obtained.

Nonlinear contractions involving simulation functions in a metric space with a partial order

2015

Very recently, Khojasteh, Shukla and Radenovic [F. Khojasteh, S. Shukla, S. Radenovic, Filomat, 29 (2015), 1189-1194] introduced the notion of Z-contraction, that is, a nonlinear contraction involving a new class of mappings namely simulation functions. This kind of contractions generalizes the Banach contraction and unifies several known types of nonlinear contractions. In this paper, we consider a pair of nonlinear operators satisfying a nonlinear contraction involving a simulation function in a metric space endowed with a partial order. For this pair of operators, we establish coincidence and common fixed point results. As applications, several related results in fixed point theory in a …

Approximation of fixed points of multifunctions in partial metric spaces

2013

Recently, Reich and Zaslavski [S. Reich and A.J. Zaslavski, Convergence of Inexact Iterative Schemes for Nonexpansive Set-Valued Mappings, Fixed Point Theory Appl. 2010 (2010), Article ID 518243, 10pages] have studied a new inexact iterative scheme for fixed points ofcontractive multifunctions. In this paper, using the partial Hausdorffmetric introduced by Aydi et al., we prove an analogous to a resultof Reich and Zaslavski for contractive multifunctions in the setting ofpartial metric spaces. An example is given to illustrate our result. 

A PU-integral on an abstract metric space.

1997

Positive solutions for parametric singular Dirichlet (p,q)-equations

2020

We consider a nonlinear elliptic Dirichlet problem driven by the (p,q)-Laplacian and a reaction consisting of a parametric singular term plus a Caratheodory perturbation f(z,x) which is (p-1)-linear as x goes to + infinity. First we prove a bifurcation-type theorem describing in an exact way the changes in the set of positive solutions as the parameter lambda>0 moves. Subsequently, we focus on the solution multifunction and prove its continuity properties. Finally we prove the existence of a smallest (minimal) solution u*_lambda and investigate the monotonicity and continuity properties of the map lambda --> u*_lambda.

On a mixed boundary value problem involving the p-Laplacian

2011

In this paper we prove the existence of infinitely many solutions for a mixed boundary value problem involving the one dimensional p-Laplacian. A result on the existence of three solutions is also established. The approach is based on multiple critical points theorems.

Viscosity solutions of the Monge-Ampère equation with the right hand side in Lp

2007

We compare various notions of solutions of Monge-Ampère equations with discontinuous functions on the right hand side. Precisely, we show that the weak solutions defined by Trudinger can be obtained by the vanishing viscosity approximation method. Moreover, we investigate existence and uniqueness of Lp-viscosity solutions.

MR2858094 Musiał, Kazimierz Pettis integrability of multifunctions with values in arbitrary Banach spaces. J. Convex Anal. 18 (2011), no. 3, 769–810.…

2012

Multiplicity of ground states for the scalar curvature equation

2019

We study existence and multiplicity of radial ground states for the scalar curvature equation $$\begin{aligned} \Delta u+ K(|x|)\, u^{\frac{n+2}{n-2}}=0, \quad x\in {{\mathbb {R}}}^n, \quad n>2, \end{aligned}$$when the function $$K:{{\mathbb {R}}}^+\rightarrow {{\mathbb {R}}}^+$$ is bounded above and below by two positive constants, i.e. $$0 0$$, it is decreasing in (0, 1) and increasing in $$(1,+\infty )$$. Chen and Lin (Commun Partial Differ Equ 24:785–799, 1999) had shown the existence of a large number of bubble tower solutions if K is a sufficiently small perturbation of a positive constant. Our main purpose is to improve such a result by considering a non-perturbative situation: we ar…

Multiplicity of Radial Ground States for the Scalar Curvature Equation Without Reciprocal Symmetry

2022

AbstractWe study existence and multiplicity of positive ground states for the scalar curvature equation $$\begin{aligned} \varDelta u+ K(|x|)\, u^{\frac{n+2}{n-2}}=0, \quad x\in {{\mathbb {R}}}^n\,, \quad n>2, \end{aligned}$$ Δ u + K ( | x | ) u n + 2 n - 2 = 0 , x ∈ R n , n > 2 , when the function $$K:{{\mathbb {R}}}^+\rightarrow {{\mathbb {R}}}^+$$ K : R + → R + is bounded above and below by two positive constants, i.e. $$0<\underline{K} \le K(r) \le \overline{K}$$ 0 < K ̲ ≤ K ( r ) ≤ K ¯ for every $$r > 0$$ r > 0 , it is decreasing in $$(0,{{{\mathcal {R}}}})$$ ( 0 , R ) and increasing in $$({{{\mathcal {R}}}},+\infty )$$ ( R , + ∞ ) for a certain $${{{\mathcal {R}}}}&g…