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<DIV><FONT face=Arial size=2>Giovedì 8 maggio 2003, alle ore 15:00 in Aula
Mancini,</FONT></DIV>
<DIV><FONT face=Arial size=2><STRONG>Prof. Yakov Pesin</STRONG> - Pennsylvania
State University - </FONT></DIV>
<DIV><FONT face=Arial size=2>"Is chaotic behavior typical among dynamical
systems?"</FONT></DIV>
<DIV align=left><FONT size=+0><FONT face=Arial size=2>Abstract:
</FONT></FONT></DIV>
<DIV align=left><FONT size=+0><FONT face=Arial size=2>The hyperbolic theory of
dynamical systems provides a mathematical foundation for the paradigm that is
widely known as "deterministic chaos" --<BR>the appearance of irregular chaotic
motions in purely deterministic dynamical<BR>systems. This phenomenon is
considered as one of the most fundamental<BR>discoveries in the theory of
dynamical systems in the second part of the last<BR>century. The hyperbolic
behavior can be interpreted in various ways and the<BR>weakest one is associated
with dynamical systems with non-zero Lyapunov<BR>exponents.<BR>I will discuss
some recent progress in the still-open problem of whether<BR>dynamical systems
with non-zero Lyapunov exponents are typical. I will also<BR>outline some
relations between this problem and recent advances in the<BR>Pugh-Shub stable
ergodicity theory.</FONT></FONT></DIV></FONT></DIV></BODY></HTML>