Sublinear Convergence of the Chord Method at Singular Points.
Soit un opérateur non nécessairement linéaire d’un Hilbert de l’équation , pour donné dans . Nous étudions la convergence du schéma itératif suivant: aou est fonction d’un opérateur auto-adjoint choisi de telle sorte que l’inversion de soit immédiate numériquement. Par exemple avec un entier et une constante convenablement choisis. Nous appliquons les résultats à un problème aux limites non linéaires avec résultats numériques.
In this study we are concerned with the problem of approximating a solution of a nonlinear equation in Banach space using Newton-like methods. Due to rounding errors the sequence of iterates generated on a computer differs from the sequence produced in theory. Using Lipschitz-type hypotheses on the mth Fréchet derivative (m ≥ 2 an integer) instead of the first one, we provide sufficient convergence conditions for the inexact Newton-like method that is actually generated on the computer. Moreover,...
We work on the research of a zero of a maximal monotone operator on a real Hilbert space. Following the recent progress made in the context of the proximal point algorithm devoted to this problem, we introduce simultaneously a variable metric and a kind of relaxation in the perturbed Tikhonov’s algorithm studied by P. Tossings. So, we are led to work in the context of the variational convergence theory.
The existence of a periodic solution of a nonlinear equation is proved. The theory developed may be used to prove the existence of a periodic solution of the variational formulation of the Navier-Stokes equations or the equations of magnetohydrodynamics. The proof of the main existence theorem is based on Rothe method in combination with the Galerkin method, using the Brouwer fixed point theorem.