Search results for " Matematica"

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.

Validation of models for sprays

2016

We consider complex fluids consisting of a dispersed phase (solid particles or liquid droplets) immersed in a gas. A class of models describing the dynamics of such a kind of systems is given by a system of partial differential equations where a kinetic equation, describing the dispersed phase, is coupled to a fluid equation for the background gas. The coupling is given by the drag force exerted by the gas on the dispersed phase. Within this class, we shall analyse the case where the kinetic equation is a Vlasov-type equation and the fluid equation are of Stokes or Navier-Stokes type. We shall discuss the validation problem for this class of models, i.e. the derivation of the equations of t…

Recensione a A. Ferrarin, "Galilei e la matematica della natura"

2015

A review of A. Ferrarin's last book about Galilei's relevance for the modern notion of science and methodology, with a particular attention to the issue of imagination as crucial for the develoment of scientific attitude.

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.

L'incertezza inSegna

2015

Traendo spunto dalla manifestazione scientifica Esperienza inSegna, dal titolo Certo è. . . probabile, svoltasi a Palermo nel 2014, in questo lavoro dapprima sono richiamati alcuni problemi che diedero la nascita al calcolo delle probabilità e successivamente vengono analizzati due problemi popolari di probabilità che normalmente sono oggetto di dibattito soprattutto tra i non addetti al settore: “Monty Hall” e il “Gratta e Vinci”. Nel primo si mostra l’importanza di tradurre correttamente, in termini di evento condizionante, l’informazione acquisita quando si vogliono “aggiornare” le probabilità; nel secondo si mette in guardia il lettore di fronte agli spot televisivi che annunciano vinci…

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

2012

Demyelination patterns in a mathematical model of multiple sclerosis.

2016

In this paper we derive a reaction-diffusion-chemotaxis model for the dynamics of multiple sclerosis. We focus on the early inflammatory phase of the disease characterized by activated local microglia, with the recruitment of a systemically activated immune response, and by oligodendrocyte apoptosis. The model consists of three equations describing the evolution of macrophages, cytokine and apoptotic oligodendrocytes. The main driving mechanism is the chemotactic motion of macrophages in response to a chemical gradient provided by the cytokines. Our model generalizes the system proposed by Calvez and Khonsari (Math Comput Model 47(7–8):726–742, 2008) and Khonsari and Calvez (PLos ONE 2(1):e…

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…