Once again KAM theory is committed in the context of nearly integrable Hamiltonian
systems. While elliptic and hyperbolic tori determine the distribution of maximal invariant tori …

A low-dimensional model of general circulation of the atmosphere is investigated. The
differential equations are subject to periodic forcing, where the period is one year. A three …

We study a generic, real analytic unfolding of a planar diffeomorphism having a fixed point
with unipotent linear part. In the analogue for vector fields an open parameter domain is …

A simple example is considered of Hill's equation ̈ x+(a^ 2+ bp (t)) x= 0, where the forcing
term p, instead of periodic, is quasi-periodic with two frequencies. A geometric exploration is …

5i+(a+ bp (t)) x= O, p (t)--p (t+ 2~),(1) where a and b are real parameters. Apparently, the first
stability diagram was drawn in the classical paper by B. vaN DER POL & MJO STI~ UTT …

The geometry of resonance tongues is considered in, mainly reversible, versions of Hill's
equation, close to the classical Mathieu case. Hill's map assigns to each value of the …

Kolmogorov–Arnold–Moser (or KAM) Theory was developed for conservative (Hamiltonian)
dynamical systems that are nearly integrable. Integrable systems in their phase space …

A universal local bifurcation analysis is presented of an autonomous Hamiltonian system
around a certain equilibrium point. This central equilibrium has a double zero eigenvalue …

We consider the perturbed quasi-periodic dynamics of a family of reversible systems with
normally 1: 1 resonant invariant tori. We focus on the generic quasi-periodic reversible Hopf …

We consider families of dynamical systems having invariant tori that carry quasi-periodic
motions. Our interest is the persistence of such tori under small, nearly-integrable …