A dynamical system is called isochronous if it features in its phase space an open, fully-
dimensional region where all its solutions are periodic in all its degrees of freedom with the …

Based on solving the Lenard recursion equations and the zero-curvature equation, we
derive the Kaup–Kupershmidt hierarchy associated with a 3× 3 matrix spectral problem …

Various solutions are displayed and analyzed (both analytically and numerically) of a
recently-introduced many-body problem in the plane which includes both integrable and …

Periodic Motions Galore: How to Modify Nonlinear Evolution Equations so that They Feature a Lot
of Periodic Solutions Page 1 Journal of Nonlinear Mathematical Physics Volume 9, Number 1 …

The existence is noted of assemblies of an arbitrary number of complex oscillators, or
equivalently, of an arbitrary even number of real oscillators, characterized by Newtonian …

A complex deformation of the Newtonian equations of motion of the classical gravitational
many-body problem is introduced, namely a many-body problem that features a parameter …

We investigate a many-body problem in the plane introduced by Calogero and intensively
studied by Calogero, Françoise and Sommacal. An ad hoc complexification transforms the …

We call partially superintegrable (indeed isochronous) those dynamical systems all
solutions of which are completely periodic with a fixed period (“isochronous”) in a part of …

For a special choice of the three interparticle coupling constants in the three-body version of
a many-body problem in the plane that was recently investigated, the general solution of the …

A technique is provided that allows to associate to a Hamiltonian another, ω-modified,
Hamiltonian, which reduces to the original one when the parameter ω vanishes, and for ω> …