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SUMMARY:Group rings and hyperbolic geometry - Grigori Avramidi (MPIM)
DTSTART:20240508T150000Z
DTEND:20240508T160000Z
UID:TALK215395@talks.cam.ac.uk
CONTACT:Oscar Randal-Williams
DESCRIPTION:Given a closed hyperbolic manifold M\, are there lower bounds 
 on the number of k-cells c_k(M) in a cell decomposition in terms of the ge
 ometry of the manifold? Gromov showed that if the manifold has injectivity
  radius at least 10^6 times (n log n)\, then there are at least n 1-cells\
 , and conjectured that injectivity radius const times log n should be enou
 gh. In this talk I will describe a result providing a lower bound on the n
 umber of k-cells for each 0 < k < dim (M). The main input is a freedom the
 orem for ideals in group rings of hyperbolic groups\, which also has other
  applications. Joint work with Thomas Delzant.  
LOCATION:MR13
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