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CATEGORIES:Algebra and Representation Theory Seminar
SUMMARY:Residual deficiency and one relator quotients of t
 riangle groups - Mariano Zeron-Medina
DTSTART;TZID=Europe/London:20121031T163000
DTEND;TZID=Europe/London:20121031T173000
UID:TALK41003AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/41003
DESCRIPTION:In the first part of the talk\, we define a real-v
 alued invariant for finitely presented groups call
 ed residual deficiency. Given a finitely presented
  group G\, its residual deficiency gives a lower b
 ound for the deficiency of some finite index subgr
 oups of G. Then we present some properties of the 
 residual deficiency and show how it relates to alr
 eady existing invariants which are used to study f
 initely presented infinite groups.\n\nIn the secon
 d part of the talk\, we show a technique that help
 s estimate the\nresidual deficiency of one relator
  quotients of triangle groups. This helps\nus conc
 lude\, under the right conditions\, that some of t
 hese groups have\nfinite index subgroups with defi
 ciency greater than one\, which as we will\nsee\, 
 is a strong property.\n
LOCATION:MR12
CONTACT:Christopher Brookes
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