We consider Hamiltonian partial differential equations utt + |δx|u + σu = f(u), x ∈T, t ∈R, with periodic boundary conditions, where f(u) is a real-analytic function of the form f(u) = u5 + σ(u5) nea...We consider Hamiltonian partial differential equations utt + |δx|u + σu = f(u), x ∈T, t ∈R, with periodic boundary conditions, where f(u) is a real-analytic function of the form f(u) = u5 + σ(u5) near u = 0, σ ∈(0, 1) is a fixed constant, and T = R/2πZ. A family of quasi-periodic solutions with 2-dimensional are constructed for the equation above with σ ∈ (0, 1)Q. The proof is based on infinite-dimensional KAM theory and partial Birkhoff normal form.展开更多
文摘We consider Hamiltonian partial differential equations utt + |δx|u + σu = f(u), x ∈T, t ∈R, with periodic boundary conditions, where f(u) is a real-analytic function of the form f(u) = u5 + σ(u5) near u = 0, σ ∈(0, 1) is a fixed constant, and T = R/2πZ. A family of quasi-periodic solutions with 2-dimensional are constructed for the equation above with σ ∈ (0, 1)Q. The proof is based on infinite-dimensional KAM theory and partial Birkhoff normal form.