Appears in collections : Jean Morlet Chair - Conference - Renormalization and Visualization in Geometry, Dynamics and number theory / Chaire Jean-Morlet - Conférence - Renormalisation et visualisation en géométrie, dynamique et théorie des nombres, The Fields Medallists, Fields medallists - 1998

The dynamics of billiards in a regular polygon can be studied from a wide range of mathematical perspectives. In this talk we will discuss connections between periodic billiard paths and number theory, modular symbols, heights and Hilbert modular varieties. In particular we will describe a new form of arithmetic chaos that emerges from dynamics in the regular 12-gon.