Search results for "Matematica"

MR3105981 81Q12 Znojil, Miloslav (CZ-AOS-N) The Coulomb potential and the paradoxes of PT symmetrization. J. Engrg. Math. 82 (2013), 173–185.

2014

Disequazioni variazionali, problemi di ottimo e convessita' generalizzata

2008

Il lavoro fatto nella tesi propone un'estensione dei principali teoremi sulle disequazioni variazionali vettoriali (VVI), considerando l'ordinamento indotto da un generico cono C di R^p (convesso, chiuso, puntato e con interno non vuoto) anziche' dal classico cono d'ordine R^p_+ . Uno dei principali risultati e' l'estensione di un risultato in [2], che lega le VVI ad una famiglia di disequazioni variazionali scalari dipendenti da un parametro. Da esso seguono alcuni dei principali teoremi di esistenza mediante il riconducimento al caso scalare. Il risultato, inoltre, insieme ad opportune ipotesi di C-convessita' generalizzata sulla funzione obiettivo, garantisce l'esistenza di soluzioni per…

*-Algebre parziali di distribuzioni

2003

Si illustra in sintesi il metodo per definire nello spazio delle distribuzioni temperate S8(R) una struttura *-algebra parziale non banale

On the Dunford property (C) for bounded linear operators SR and RS

2011

In this paper we show that if S in L(X; Y ) and R in L(Y;X), X and Y complex Banach spaces, then the products RS and SR share the Dunford property (C)

Existence and multiplicity of solutions for non linear elliptic Dirichlet systems

2012

The existence and multiplicity of solutions for systems of nonlinear elliptic equations with Dirichlet boundary conditions is investigated. Under suitable assumptions on the potential of the nonlinearity, the existence of one, or two, or three solutions is established. Our approach is based on variational methods.

Simple epidemic model by a Markov chain

2008

In this paper we propose a continuous-time Markov chain to describe a SIs model with and without external reinfection

Extended Thermodynamics of Turbolent Superfluids:Nonlinear Costitutive Theory

2008

In this paper we extend to nonlinear regimes a thermodynamical model of inhomogeneous superfluid turbulence previously formulated. The theory chooses as fundamental fields the density, the velocity, the energy density, the heat flux and the averaged vortex line length per unit volume. The relations which constrain the constitutive quantities are deduced from the entropy principle, using the Liu method of Lagrange multipliers. Using a Legendre transformation, in the paper it is shown that the constitutive theory is determined by the choice of only two scalar functions of the intrinsic Lagrange multipliers.

MR3269340 Reviewed O'Regan, Donal Lefschetz type theorems for a class of noncompact mappings. J. Nonlinear Sci. Appl. 7 (2014), no. 5, 288–295. (Revi…

2015

Lefschetz fixed-point theorem furnishes a way for counting the fixed points of a suitable mapping. In particular, the Lefschetz fixed-point theorem states that if Lefschetz number is not zero, then the involved mapping has at least one fixed point, that is, there exists a point that does not change upon application of mapping. ewline Let $f={f_q}:E o E$ be an endomorphism of degree zero of graded vector space $E={E_q}$. Let $ ilde{E}=E setminus {x in E : f^n(x)=0, mbox{ for some }n in mathbb{N}}$. Define the generalized Lefschetz number $Lambda(f)$ by $$Lambda(f)=sum_{q geq 0}(-1)^qmbox{Tr}(f_q),$$ where $mbox{Tr}(f)=mbox{tr}( ilde{f})$ is the generalized trace of $f$, ``tr'' is the ordinar…

A generalized first-return integration process

2020

We extend the first-return integration process, introduced in [5] by U.B. Darji and M.J. Evans, and prove that each Lebesgue-improper integrable function f : [a, b] --> R is first-return integrable in this generalized sense to (Li)int_a^b f(t) dt.

Remarks on the first return integral

2007

Some pathological properties of the first-return integrals are explored. In particular it is proved that there exist Riemann improper integrable functions which are first-return recoverable almost everywhere, but not first-return integrable, with respect to each trajectory. It is also proved that the usual convergence theorems fail to be true for the first-return integrals.