Search results for "Matematica"
showing 10 items of 1637 documents
Common fixed point theorems for (ϕ, ψ)-weak contractions in fuzzy metric spaces
2010
Motivated by Rhoades (Nonlinear Anal., 47 (2001), 2683--2693), on the lines of Khan et al. (Bull. Aust. Math. Soc., 30 (1984), 1-9) employing the idea of altering distances, we extend the notion of (ϕ, ψ)-weak contraction to fuzzy metric spaces and utilize the same to prove common fixed point theorems for four mappings in fuzzy metric spaces.
Edelstein-Suzuki-type resuls for self-mappings in various abstract spaces with application to functional equations
2016
Abstract The fixed point theory provides a sound basis for studying many problems in pure and applied sciences. In this paper, we use the notions of sequential compactness and completeness to prove Eldeisten-Suzuki-type fixed point results for self-mappings in various abstract spaces. We apply our results to get a bounded solution of a functional equation arising in dynamic programming.
A fixed point theorem in G-metric spaces via alpha-series
2014
In the context of G-metric spaces we prove a common fixed point theorem for a sequence of self mappings using a new concept of alpha-series.
MR3136553 Reviewed Popa, Valeriu; Patriciu, Alina-Mihaela A general fixed point theorem for pairs of mappings satisfying implicit relations in two G-…
2014
In [Stud. Cercet. Ştiinţ. Ser. Mat. Univ. Bacău No. 7 (1997), 127–133 (1999); MR1721711], V. Popa initiated the study of fixed points for mappings satisfying implicit relations as a way to unify and generalize various contractive conditions. Later on, many papers were published extending this approach to different metric settings. In the paper under review, the authors prove a result of such type for two mappings defined on two generalized metric spaces, called G-metric spaces and introduced by Z. Mustafa and B. Sims [J. Nonlinear Convex Anal. 7 (2006), no. 2, 289–297; MR2254125 (2007f:54049)].
Atti GIORNATE DI STUDIO DELL'INSEGNANTE DI MATEMATICA (GIMat).Le mani, la parola, la testa: capire, argomentare, dimostrare in matematica
2022
Nello spirito di sempre, gli atti del convegno, pubblicati prima del convegno stesso, vogliono offrire ai lettori, anche attraverso i 25 contributi scritti/presentati da insegnanti, insegnanti/ricercatori e ricercatori universitari intervenuti a GIMat 2022 e riportati di seguito, la possibilità di riflettere prima, durante e dopo le stesse GIMat su tante esperienze portate avanti sul territorio nazionale e internazionale, nell’ambito dell’Educazione matematica
Fixed point results for $GP_(Λ,Θ)$-contractive mappings
2014
In this paper, we introduce new notions of GP-metric space and $GP_(Λ,Θ)$-contractive mapping and then prove some fixed point theorems for this class of mappings. Our results extend and generalized Banach contraction principle to GP-metric spaces. An example shows the usefulness of our results.
Anisotropic Navier Kirchhoff problems with convection and Laplacian dependence
2022
We consider the Navier problem-Delta(2)(k,p)u(x)=f(x,u(x), del u(x), Delta u(x)) in Omega, u vertical bar(partial derivative Omega) =Delta u vertical bar(partial derivative Omega) = 0,driven by the sign-changing (degenerate) Kirchhoff type p(x)-biharmonic operator, and involving a (del u, Delta u)-dependent nonlinearity f. We prove the existence of solutions, in weak sense, defining an appropriate Nemitsky map for the nonlinearity. Then, the Brouwer fixed point theorem assessed for a Galerkin basis of the Banach space W-2,W-p(x)(Omega)boolean AND W-0(1,p(x))(Omega) leads to the existence result. The case of nondegenerate Kirchhoff type p(x)-biharmonic operator is also considered with respec…
Wavefront invasion for a chemotaxis model of Multiple Sclerosis
2016
In this work we study wavefront propagation for a chemotaxis reaction-diffusion system describing the demyelination in Multiple Sclerosis. Through a weakly non linear analysis, we obtain the Ginzburg–Landau equation governing the evolution of the amplitude of the pattern. We validate the analytical findings through numerical simulations. We show the existence of traveling wavefronts connecting two different steady solutions of the equations. The proposed model reproduces the progression of the disease as a wave: for values of the chemotactic parameter below threshold, the wave leaves behind a homogeneous plaque of apoptotic oligodendrocytes. For values of the chemotactic coefficient above t…
Moderately close Neumann inclusions for the Poisson equation
2016
We investigate the behavior of the solution of a mixed problem for the Poisson equation in a domain with two moderately close holes. If ϱ1 and ϱ2 are two positive parameters, we define a perforated domain Ω(ϱ1,ϱ2) by making two small perforations in an open set: the size of the perforations is ϱ1ϱ2, while the distance of the cavities is proportional to ϱ1. Then, if r∗ is small enough, we analyze the behavior of the solution for (ϱ1,ϱ2) close to the degenerate pair (0,r∗). Copyright © 2016 John Wiley & Sons, Ltd.
Solutions for parametric double phase Robin problems
2021
We consider a parametric double phase problem with Robin boundary condition. We prove two existence theorems. In the first the reaction is ( p − 1 )-superlinear and the solutions produced are asymptotically big as λ → 0 + . In the second the conditions on the reaction are essentially local at zero and the solutions produced are asymptotically small as λ → 0 + .