• Geography of resonances and Arnold diffusion in a priori unstable Hamiltonian systems 

      Delshams Valdés, Amadeu; Huguet Casades, Gemma (2008-12-08)
      Article
      Accés obert
      In the present paper we consider the case of a general $\cont{r+2}$ perturbation, for $r$ large enough, of an a priori unstable Hamiltonian system of $2+1/2$ degrees of freedom, and we provide explicit conditions on it, ...
    • KAM theory and a partial justification of Greene's criterion for non-twist maps 

      Delshams Valdés, Amadeu; Llave Canosa, Rafael de la (1999)
      Article
      Accés obert
      We consider perturbations of integrable area preserving non twist maps of the annulus those are maps in which the twist condition changes sign These maps appear in a variety of applications notably transport in atmospheric ...
    • Lindstedt series for lower dimensional tori 

      Jorba, Angel; Llave Canosa, Rafael de la; Zou, Maorong (1995)
      Article
      Accés obert
      We consider the existence and effective computation of low-dimensional (less independent frequencies than degrees of freedom) invariant tori of a near-integrable system. Lindstedt method is a systematic procedure to compute ...
    • On quasiperiodic perturbations of elliptic equilibrium points 

      Jorba, Angel; Simó Torres, Carlos (1995)
      Article
      Accés obert
      This work focusses on quasiperiodic time-dependent perturbations of ordinary differential equations near elliptic equilibrium points. This means studying $$ \dot{x}=(A+\varepsilon Q(t,\varepsilon))x+\varepsilon ...