title: A new result on the existence of periodic solutions for Liénard equations with a singularity of repulsive type.
abstract: In this paper, the problem of the existence of a periodic solution is studied for the second order differential equation with a singularity of repulsive type [Formula: see text] where [Formula: see text] is singular at [Formula: see text],φandhareT-periodic functions. By using the continuation theorem of Manásevich and Mawhin, a new result on the existence of positive periodic solution is obtained. It is interesting that the sign of the function [Formula: see text] is allowed to change for [Formula: see text].
authors.affiliation: College of Math & Statistics, Nanjing University of Information Science and Technology, Nanjing, 210044 China.
authors.forename: Shiping
authors.initials: S
authors.lastname: Lu
keywords: Liénard equation; periodic solution; singularity; topological degree