Contributions to Nonlinear Analysis

This paper is concerned with the existence and uniform decay rates of solutions of the waveequation with a sourceterm and subject to nonlinear boundary damping ? ? u ? ? u =|u| u in ? ×(0, +?) ? tt ? ? ? ? u=0 on ? ×(0, +?) 0 (1. 1) ? ? u+g(u)=0 on ? ×(0, +?) ? t 1 ? ? ? ? 0 1 u(x, 0) = u (x); u (x, 0) = u (x), x? ? , t n where ? is a bounded domain of R , n? 1, with a smooth boundary ? = ? ? ? . 0 1 Here, ? and ? are closed and disjoint and ? represents the unit outward normal 0 1 to ? . Problems like (1. 1), more precisely, ? u ? ? u =? f (u)in? ×(0, +?) ? tt 0 ? ? ? ? u=0 on ? ×(0, +?) 0 (1. 2) ? ? u =? g(u )? f (u)on? ×(0, +?) ? t 1 1 ? ? ? ? 0 1 u(x, 0) = u (x); u (x, 0) = u (x), x? ? , t were widely studied in the literature, mainly when f =0, see[6, 13, 22]anda 1 long list of references therein. When f =0and f = 0 this kind of problem was 0 1 well studied by Lasiecka and Tataru [15] for a very general model of nonlinear functions f (s), i=0, 1, but assuming that f (s)s? 0, that is, f represents, for i i i each i, an attractive force.

Remarks on a Class of Neumann Problems Involving Critical Exponents. - Existence of Solutions for a Class of Problems in IR N Involving the p(x)-Laplacian. - A Unitarian Approach to Classical Electrodynamics: The Semilinear Maxwell Equations. - Existence of Solutions for the Nonlinear Schrödinger Equation with V (?) = 0. - Asymptotic Behavior of a Bernoulli-Euler Type Equation with Nonlinear Localized Damping. - T-minima. - A Note on Heteroclinic Solutions of Mountain Pass Type for a Class of Nonlinear Elliptic PDE s. - Existence of Multiple Solutions for Quasilinear Equations via Fibering Method. - Symmetry of Solutions of a Semilinear Elliptic Problem in an Annulus. - Construction of a Radial Solution to a Superlinear Dirichlet Problem that Changes Sign Exactly Once. - Global Solvability and Asymptotic Stability for the Wave Equation with Nonlinear Boundary Damping and Source Term. - Multiscale Asymptotic Behavior of a Solution of the Heat Equation on . - Positive Solutions for a Class of Nonlocal Elliptic Problems. - On a Class of Critical Elliptic Equations of Caffarelli-Kohn-Nirenberg Type. - Existence and Number of Solutions for a Class of Semilinear Schrödinger Equations. - Multiparameter Elliptic Equations in Annular Domains. - Variational Principle for the Seiberg-Witten Equations. - Some Recent Results on Equations Involving the Pucci s Extremal Operators. - Principal Eigenvalue in an Unbounded Domain and a Weighted Poincaré Inequality. - Uniform Stabilization for a Hyperbolic Equation with Acoustic Boundary Conditions in Simple Connected Domains. - Some Remarks on Semilinear Resonant Elliptic Problems. - Remarks on Regularity Theorems for Solutions to Elliptic Equations via the Ultracontractivity of the Heat Semigroup. - 2d Ladyzhenskaya-Solonnikov Problem forInhomogeneous Fluids. - Generalization of a Well-known Inequality. - Nonexistence of Nontrivial Solutions for Supercritical Equations of Mixed Elliptic-Hyperbolic Type. - On the Shape of Least-Energy Solutions to a Quasilinear Elliptic Equation Involving Critical Sobolev Exponents. - A-priori Bounds and Positive Solutions to a Class of Quasilinear Elliptic Equations. - The Role of the Equal-Area Condition in Internal and Superficial Layered Solutions to Some Nonlinear Boundary Value Elliptic Problems. - Some Recent Results Regarding Symmetry and Symmetry-breaking Properties of Optimal Composite Membranes. - Generic Simplicity for the Solutions of a Nonlinear Plate Equation. - An Estimate for the Blow-up Time in Terms of the Initial Data. - Lorentz Spaces and Nonlinear Elliptic Systems. - The Topology of Critical Sets of Some Ordinary Differential Operators. - A Note on the Superlinear Ambrosetti-Prodi Type Problem in a Ball.