Almost periodic solutions for a class of higher-dimensional beam equations

作者:Niu Huawei*; Geng Jiansheng
来源:Nonlinearity, 2007, 20(11): 2499-2517.
DOI:10.1088/0951-7715/20/11/003

摘要

In this paper, we show that there are many almost periodic solutions corresponding to full- dimensional invariant tori for higher- dimensional beam equations with Fourier multiplier
u(tt) + (- Delta + M xi)(2) u + f (u) = 0,
subject to periodic boundary conditions, where the nonlinearity f is a real-analytic function near u = 0 with f (0) = f '(0) = 0. The proof is based on an improved infinite- dimensional KAM theorem.