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Compactification of $$\mathbb{R}^ k$$-actions and Hamiltonian systems of toric type. (Compactification d’actions de $$\mathbb{R}^ k$$ et systèmes hamiltoniens de type torique.) (French) Zbl 0810.58015
The author’s summary: “Let’s consider a Hamiltonian system $$(M, \omega, H)$$ endowed with a finite dimensional space $$\mathcal A$$ of first integrals. The center of $$\mathcal A$$ for the Poisson brackets defines an infinitesimal Hamiltonian action of $$R^ k$$ on $$M$$. If $$F$$ is a compact orbit of this action, we show that a reasonable hypothesis on the function jets gives a normal form of “toric type” in a neighbourhood of $$F$$. This result, conjectured by P. Molino [Sémin. Gaston Darboux, Géom. Topologie Différ. 1989-1990, No. 5, 39-47 (1991; Zbl 0734.70013)], generalizes the theorems of Arnold-Liouville, Eliasson, Nekhoroshev and its version with singularities of Dufour. The key of the proof is an “$$R$$-action compactification” theorem which extends a result of J. P. Dufour and P. Molino”.

##### MSC:
 37J99 Dynamical aspects of finite-dimensional Hamiltonian and Lagrangian systems