Global bifurcations of closed invariant curves in two-dimensional maps: a computer assisted study, Int. from an invariant circle for two-parameter families of maps of the plane: A computer-assisted study, Comm. The Bogdanov map: bifurcations, mode locking, and chaos in a dissipative system, Int.
We examine existence and stability of relative equilibria of the n-vortex problem specialized to the case where N vortices have small and equal circulation and one vortex has large circulation. As the small circulation tends to zero, the weak vortices tend to a circle centered on the strong vortex. A special potential function of this limiting problem can… (More)
In this paper we examine the question of existence of a two-dimensional universally observable system, i.e., dynamics which are observable by every continuous nonconstant real-valued function on the state space. We are motivated by the work of D. McMahon, who proved that a class of three-dimensional manifolds with horocycle flow have this property. We… (More)
The aim of this work is to provide an insight of an idealized model of a planetary ring. The model is a limit case of the planar circular restricted 1+n body problem, where an infinitesimal particle moves under the gravitational influence of a large central body and n smaller bodies located on the vertices of a regular n-gon. When considering n tending to… (More)
For a class of potential functions including those used for the planar n-body and n-vortex problems, we investigate co-circular central configurations whose center of mass coincides with the center of the circle containing the bodies. Useful equations are derived that completely describe the problem. Using a topological approach, it is shown that for any… (More)