85 research outputs found

    Multiple nonsymmetric nodal solutions for quasilinear Schrödinger system

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    In this paper, we consider the quasilinear Schrödinger system in RN (N ≥ 3): −∆u + A(x)u − 1 2 ∆(u 2 )u = 2α |u| α−2u|v| −∆v + Bv − 1 2 ∆(v 2 )v = 2β |u| |v| β−2 v, where α, β > 1, 2 0 is a constant. By using a constrained minimization on Nehari–Pohožaev set, for any given integer s ≥ 2, we construct a nonradially symmetrical nodal solution with its 2s nodal domains

    Multiple nonsymmetric nodal solutions for quasilinear Schrödinger system

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    In this paper, we consider the quasilinear Schrödinger system in RN (N ≥ 3): −∆u + A(x)u − 1 2 ∆(u 2 )u = 2α |u| α−2u|v| −∆v + Bv − 1 2 ∆(v 2 )v = 2β |u| |v| β−2 v, where α, β > 1, 2 0 is a constant. By using a constrained minimization on Nehari–Pohožaev set, for any given integer s ≥ 2, we construct a nonradially symmetrical nodal solution with its 2s nodal domains

    Approximation of small-amplitude weakly coupled oscillators with discrete nonlinear Schrodinger equations

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    Small-amplitude weakly coupled oscillators of the Klein-Gordon lattices are approximated by equations of the discrete nonlinear Schrodinger type. We show how to justify this approximation by two methods, which have been very popular in the recent literature. The first method relies on a priori energy estimates and multi-scale decompositions. The second method is based on a resonant normal form theorem. We show that although the two methods are different in the implementation, they produce equivalent results as the end product. We also discuss applications of the discrete nonlinear Schrodinger equation in the context of existence and stability of breathers of the Klein--Gordon lattice

    International Conference on Nonlinear Differential Equations and Applications

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    Dear Participants, Colleagues and Friends It is a great honour and a privilege to give you all a warmest welcome to the first Portugal-Italy Conference on Nonlinear Differential Equations and Applications (PICNDEA). This conference takes place at the Colégio Espírito Santo, University of Évora, located in the beautiful city of Évora, Portugal. The host institution, as well the associated scientific research centres, are committed to the event, hoping that it will be a benchmark for scientific collaboration between the two countries in the area of mathematics. The main scientific topics of the conference are Ordinary and Partial Differential Equations, with particular regard to non-linear problems originating in applications, and its treatment with the methods of Numerical Analysis. The fundamental main purpose is to bring together Italian and Portuguese researchers in the above fields, to create new, and amplify previous collaboration, and to follow and discuss new topics in the area

    Stability and instability of expanding solutions to the Lorentzian constant-positive-mean-curvature flow

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    We study constant mean curvature Lorentzian hypersurfaces of R1,d+1\mathbb{R}^{1,d+1} from the point of view of its Cauchy problem. We completely classify the spherically symmetric solutions, which include among them a manifold isometric to the de Sitter space of general relativity. We show that the spherically symmetric solutions exhibit one of three (future) asymptotic behaviours: (i) finite time collapse (ii) convergence to a time-like cylinder isometric to some R×Sd\mathbb{R}\times\mathbb{S}^d and (iii) infinite expansion to the future converging asymptotically to a time translation of the de Sitter solution. For class (iii) we examine the future stability properties of the solutions under arbitrary (not necessarily spherically symmetric) perturbations. We show that the usual notions of asymptotic stability and modulational stability cannot apply, and connect this to the presence of cosmological horizons in these class (iii) solutions. We can nevertheless show the global existence and future stability for small perturbations of class (iii) solutions under a notion of stability that naturally takes into account the presence of cosmological horizons. The proof is based on the vector field method, but requires additional geometric insight. In particular we introduce two new tools: an inverse-Gauss-map gauge to deal with the problem of cosmological horizon and a quasilinear generalisation of Brendle's Bel-Robinson tensor to obtain natural energy quantities.Comment: Version 2: 60 pages, 1 figure. Changes mostly to fix typographical errors, with the exception of Remark 1.2 and Section 9.1 which are new and which explain the extrinsic geometry of the embedding in more detail in terms of the stability result. Version 3: updated reference

    Minimal positive solutions for systems of semilinear elliptic equations

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    The paper is devoted to a system of nonlinear PDEs containing gradient terms. Applying the approach based on Sattinger's iteration procedure we use sub and supersolutions methods to prove the existence of positive solutions with minimal growth. These results can be applied for both sublinear and superlinear problems

    Nonexistence and optimal decay of supersolutions to Choquard equations in exterior domains

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    We consider a semilinear elliptic problem with a nonlinear term which is the product of a power and the Riesz potential of a power. This family of equations includes the Choquard or nonlinear Schroedinger--Newton equation. We show that for some values of the parameters the equation does not have nontrivial nonnegative supersolutions in exterior domains. The same techniques yield optimal decay rates when supersolutions exists.Comment: 47 pages, 8 figure

    LECTURES ON NONLINEAR DISPERSIVE EQUATIONS I

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    CONTENTS J. Bona Derivation and some fundamental properties of nonlinear dispersive waves equations F. Planchon Schr\"odinger equations with variable coecients P. Rapha\"el On the blow up phenomenon for the L^2 critical non linear Schrodinger Equatio
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