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Tesi etd-05082007-131542


Thesis type
Tesi di laurea specialistica
Author
Beraldo, Dario
URN
etd-05082007-131542
Title
Geodesic flows on moduli spaces, continued fractions and Lyapunov exponents
Struttura
SCIENZE MATEMATICHE, FISICHE E NATURALI
Corso di studi
MATEMATICA
Commissione
Relatore Marmi, Stefano
Parole chiave
  • Lyapunov spectrum
  • translation surface
  • geodesic flow
  • teichmuller space
  • renormalization
  • interval exchange map
  • continued fraction
  • linear cocycles
  • mutiplicative ergodic theorem
Data inizio appello
25/05/2007;
Consultabilità
completa
Riassunto analitico
Translation surfaces (i.e. closed Riemann surfaces with a holomorphic 1-form) arise in many problems of topology, dynamics, algebraic geometry and so on. <br>They are naturally organized into families (called strata of the moduli space), according to genus and nature of singularities: each stratum is a complex orbifold of finite dimension. Consequently, there exists a well-defined geodesic flow, called Teichmuller flow, whose (ergodic) properties are worth to be studied. This can be achieved by representing translation surfaces as suspensions over interval exchange maps, whose combinatorical properties play a crucial role, and then defining the appropriate renormalization operators (Rauzy-Veech and Zorich renormalization maps).<br>In genus one, everything is well-known: the Teichmuller flow is just the geodesic flow on the modular surface, which has much to do with continued fractions.<br>In this thesis we present some analogies between the simple case of genus one and the general case. In particular we present the Zorich cocycle as a generalization of the Gauss map, and we prove that its Lyapunov spectrum is simple (a theorem due to A. Avila, M. Viana, 2005-2006).<br>
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