One-end finitely presented groups acting on the circle
Résumé
We study possible one-end finitely presented subgroups of Diff(+)(omega)(S-1), acting without finite orbits. Our main result, theorem 1, establishes that any such action possesses the so-called property (star), that allows one to make distortion-controlled expansion and is thus sufficient to conclude that the action is Lebesgue-ergodic. We also propose a path towards full characterization of such actions (conjectures 3-5).