In this paper,we prove the existence of positive quasi-periodic solutions for a class of Lotka-Volterra system with quasi-periodic coefficients by KAM technique.
In this paper, we establish an estimate for the solutions of small-divisor equation of higher order with large variable coefficient. Then by formulating an infinite-dimensional KAM theorem which allows for multiple normal frequencies and unbounded perturbations, we prove that there are many periodic solutions for the coupled KdV equation subject to small Hamiltonian perturbations.
