## Sur les courbes invariantes par les difféomorphismes de l’anneau. Vol. 1. Complété par un appendice au chapitre 1 de Albert Fathi.(French)Zbl 0532.58011

Astérisque, 103-104. Publié avec le Concours du Centre National de la Recherche Scientifique. Paris: Sociéte Mathématique de France. 221 p. (1983).
This publication, constituted by four chapters, deals with invariant closed curves, and rings of instability in the sense of Birkhoff, for some conservative surface transformations (twist map of an annulus A here). Chapter 1 gives in a different language an exposition of a part of the results of G. D. Birkhoff [Acta Math. 43, 1-119 (1920); Ann. Inst. Henri Poincaré 2, 369-386 (1932; Zbl 0005.22103)] for the analytical case. In particular a more topological proof of Birkhoff’s theorem about curves being graphs is laid. The problem of instability rings is exposed from more recent results of Robinson and Moser. Chapter 2 shows that Moser’s invariant curve theorem is optimal up to $$\epsilon>0$$, and that usually for $$C^{3-\epsilon}$$-perturbations of a $$C^\infty$$-complete integrable monotone twist map, there exists no invariant curve of a fixed rotation number (another proof is also given in chapter 3). In this chapter counterexamples to stability for $$C^{2-\epsilon}$$-perturbations can be found. Chapter 3 is devoted in part to some insight of the geometry of the set of ”standard-diffeomorphisms” of A that leave invariant a curve, after another proof of a chapter 2 result. This proof is based on a counterexample of Denjoy. Chapter 4 proves Rüssmann’s translated curve theorem in class $$C^{3+\epsilon}$$, $$\epsilon>0$$, if one restricts the rotation number on the translated curve to be a number of constant type. This theorem is a nonconservative generalization of Moser’s invariant curve theorem.
Reviewer: C.Mira

### MSC:

 37C75 Stability theory for smooth dynamical systems 57R50 Differential topological aspects of diffeomorphisms 39A11 Stability of difference equations (MSC2000) 58C25 Differentiable maps on manifolds 58-02 Research exposition (monographs, survey articles) pertaining to global analysis 57-02 Research exposition (monographs, survey articles) pertaining to manifolds and cell complexes

Zbl 0005.22103