Search results for "Matematica"
showing 10 items of 1637 documents
MR2410211 (2009b:47107) Păcurar, Mădălina Viscosity approximation of fixed points with $\phi$-contractions. Carpathian J. Math. 24 (2008), no. 1, 88-…
2009
Let T be a nonexpansive self-mapping of a closed bounded convex subset Y of a Hilbert space. For l in (0, 1), the author considers the iteration xl = lf(xl)+(1−l)Txl, where f from Y to Y is a $\phi$-contraction. Then, the author proves that (xl)l converges strongly as l goes to 0 to the unique fixed point of the $\phi$-contraction Pof, where P is the metric projection of Y onto the set FT of fixed points of T. The viscosity approximation method of the paper is obtained from the method proposed by A. Moudafi [J. Math. Anal. Appl. 241 (2000), no. 1, 46–55; MR1738332 (2000k:47085)] for mappings in Hilbert spaces, and by H. K. Xu [J. Math. Anal. Appl. 298 (2004), no. 1, 279–291; MR2086546 (2005…
Positive and nodal solutions for nonlinear nonhomogeneous parametric neumann problems
2020
We consider a parametric Neumann problem driven by a nonlinear nonhomogeneous differential operator plus an indefinite potential term. The reaction term is superlinear but does not satisfy the Ambrosetti-Rabinowitz condition. First we prove a bifurcation-type result describing in a precise way the dependence of the set of positive solutions on the parameter λ > 0. We also show the existence of a smallest positive solution. Similar results hold for the negative solutions and in this case we have a biggest negative solution. Finally using the extremal constant sign solutions we produce a smooth nodal solution.
MR2544061 Ludkovsky, S. V. Algebras of operators in Banach spaces over the quaternion skew field and the octonion algebra. J. Math. Sci. (N. Y.) 144 …
2010
The overland flow equation for constant rainfall excess: an evaluation of runoff volume and time to equilibrium
2011
In this paper we study the runoff volume V(t) per unit area generated by the overland flow in the time interval [0,t], under a stationary rainfall r and initially dry conditions. For all positive values of the rating exponent m we express V(t) in closed form in terms of the solution q(t) of the overland flow equation. We define a simpler, approximated value of V(t) and show that, for m≥1, the error is smaller than a quantity of the form c e^{-pt}. Finally, for 1≤m≤3, we find an explicit upper bound for the time to equilibrium t_e, by showing that q(t) differs from the equilibrium outflow r by a quantity of the form c e^{-pt}.
MR2905225 Rowe, Stephen; Fang, Junsheng; Larson, David R. P1 subalgebras of Mn(C). Involve 4 (2011), no. 3, 213–250. (Reviewer: Camillo Trapani)
2012
A note on partial*–algebras and spaces of distributions
2014
Given a rigged Hilbert space (D,H,D'), the spaces D_{loc are considered. It is shown that, if D is a Hilbert *-algebra, D_{loc} carry out a natural structure of partial *-algebra. Furthermore, on D_{loc} it is defined a topology, so that D_{loc} is an interspace. Examples from distributions theory are considered.
Incontri matematici del terzo tipo
2019
Il Piano Lauree Scientifiche (PLS) `e oggi il principale programma di orientamento universitario in ambito scientifico operante in Italia. Esso nasce con il nome di Progetto Lauree Scientifiche nel 2004 dalla collaborazione tra il Ministero dell’Istruzione, dell’Universit`a e della Ricerca (MIUR), la Conferenza dei Presidi di Scienze e Teconologia (Con.Scienze), e Confindustria, con l’obiettivo principale di fare fronte alla riduzione degli studenti iscritti ai corsi di laurea scientifici, principalmente in matematica, fisica e chimica
Perturbations of polaroid type operators on Banach spaces and Applications
2011
We study the permanence of polaroid type conditions under perturbations
Property (gR) and perturbations
2012
Property (gR) holds for a bounded linear operator T defined on a complex Banach space X, the isolated points of the spectrum of T which are eigenvalues of finite multiplicity are exactly those points c of the approximate point spectrum such cI -T is upper semi B-Browder. In this paper we consider the permanence of this property under nilpotent, perturbations commuting with T.