seminar: Reducibility of quasiperiodic linear systems under a Brjuno-Rüssmann arithmetical condition
speaker: Claire Chavaudret (Centro di Ricerca Matematica Ennio De Giorgi)abstract: Linear quasiperiodic systems can have complicated dynamics, however they are well understood in the case when they are reducible, i.e when they can be conjugated to a system with constant coefficients. If the frequency vector of the system is diophantine, it is known that reducibility happens most of the time. As in other linearization problems, there is the problem of finding an optimal arithmetical condition on the frequency vector (and, in 2-dimensional systems, on the rotation number) which will imply reducibility. Using a slow convergence KAM scheme, we will see a link between reducibility of 2-dimensional quasiperiodic systems and a Brjuno condition (which is weaker than the diophantine condition) both on the frequency vector and on the rotation number.
timetable:
Wed 16 Nov, 15:30 - 16:30, Sala Conferenze Centro De Giorgi
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