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SUMMARY:The flat closing problem - Bruno Martelli (Università di Pisa)
DTSTART:20260206T134500Z
DTEND:20260206T144500Z
UID:TALK241645@talks.cam.ac.uk
CONTACT:Macarena Arenas
DESCRIPTION:The Flat Closing Problem is the following 1993 question of Gro
 mov: Let X be a proper CAT(0) space and Γ be a discrete group acting prop
 erly and co-compactly by isometries on X. Does the existence of a flat pla
 ne in X imply that Γ contains a copy of ZxZ?\nWe will show that this ques
 tion has a negative answer. The counterexample arises from a 4-dimensional
  pseudo-Anosov homeomorphism whose mapping torus is a hyperbolic 5-manifol
 d.\n
LOCATION:MR13
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