Citation: | Meina Gao. QUASI-PERIODIC SOLUTIONS FOR 1D NONLINEAR WAVE EQUATION[J]. Journal of Applied Analysis & Computation, 2023, 13(3): 1505-1534. doi: 10.11948/20220334 |
In this paper, one-dimensional (1D) nonlinear wave equation
$ u_{tt}-u_{xx}+mu+u^{7}=0 $
on the finite $ x $-interval $ [0, \pi] $ with Dirichlet boundary conditions is considered. It is proved that there are many $ 3 $-dimensional elliptic invariant tori, and thus quasi-periodic solutions for the above equation. This is an extension of the previous work [
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