In this paper, we study positive periodic solutions to the repulsive singular perturbations of
the Hill equations. It is proved that such a perturbation problem has at least two positive …

Mathematical Models with Singularities Page 1 Mathematical Models with Singularities Pedro
J. Torres A Zoo of Singular Creatures Atlantis Briefsin Differential Equations Series …

We study the existence of twist periodic solutions of second order differential equations with
an attractive–repulsive singularity. Such twist periodic solutions are stable in the sense of …

After establishing a relation between the Hill's equations and the Emarkov-Pinney
equations, we are able to use degree theory to remove a technical assumption in [14], and …

Motivated by the Lazer–Solimini equation and the Brillouin equation, which present a
repulsive singularity at the origin, we will develop in this paper some criterion for the …

It is proved that a periodically forced second-order equation with a singular nonlinearity in
the origin with linear growth in infinity possesses a-periodic stable solution for high values of …

This article considers the existence and linear stability of positive periodic solutions for the
Nathanson's model and the Comb-drive finger model of Micro-Electro-Mechanical-Systems …

For the Gylden-Meshcherskii-type problem with a periodically changing gravitational
parameter, we prove the existence of radially periodic solutions with high angular …

In this work we consider the existence of solutions of a Dirichlet problem with a prescribed
number of zeros for a large class of second order differential equations with singularities …

In this paper we present a sufficient condition for the stability of the equilibrium of a nonlinear
planar system. The proof is based on the computation of the corresponding Birkhoff normal …