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SUMMARY:How to quickly generate a nice hyperbolic element - Emmanuel Breui
 llard (Universität Münster)
DTSTART:20170512T123000Z
DTEND:20170512T133000Z
UID:TALK72513@talks.cam.ac.uk
CONTACT:INI IT
DESCRIPTION:In the 60&#39\;s Rota and Strang defined the notion of joint s
 pectral radius of a finite set of matrices. This adequately generalizes th
 e spectral radius of a single matrix to several matrices\, and the relatio
 n between the limit norm of powers and the maximal eigenvalue (spectral ra
 dius formula) can be extended to this setting. In this talk I will present
  a general geometric formulation in which one considers a finite set of is
 ometries S and the joint minimal displacement L(S)\, which is closely rela
 ted to the joint spectral radius of Rota and Strang. The main result is a 
 spectral radius formula for&nbsp\;isometric actions on spaces with non-pos
 itive curvature (in particular symmetric spaces of non-compact type and \\
 delta-hyperbolic spaces)&nbsp\;which extends the&nbsp\;previously known re
 sults about matrices. Applications to uniform exponential growth will be g
 iven. Joint work with Koji Fujiwara.
LOCATION:Seminar Room 1\, Newton Institute
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