3 papers
math.DS2018
Normalization of rationally integrable systems
Nguyen Tien Zung
In two previous papers we showed that any analytically integrable vector field admits a local analytic Poincaré-Birkhoff normalization in the neighborhood of a singular point. The…
math.DS2017
A conceptual approach to the problem of action-angle variables
Nguyen Tien Zung
In this paper we develop a general conceptual approach to the problem of existence of action-angle variables for dynamical systems, which establishes and uses the fundamental conse…
math.SG2017
Convexity of singular affine structures and toric-focus integrable Hamiltonian systems
Tudor Ratiu, Christophe Wacheux, Nguyen Tien Zung
This work is devoted to a systematic study of symplectic convexity for integrable Hamiltonian systems with elliptic and focus-focus singularities. A distinctive feature of these sy…