摘要：In this paper we study the second-order periodic system: x ″ + V ′ ( x ) + p ( t ) g ( x ) = F x ( x , t ) where V ( x ) has a singularity. Under some assumptions on the V, F, g, and p, by Ortega’s small twist theorem, we obtain the existence of quasi-periodic solutions and boundedness of all the solutions.
关键词：isochronous oscillators ; repulsive singularity ; small twist theorem ; quasi-periodic solutions ; boundedness of solution
