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CATEGORIES:Geometric Group Theory (GGT) Seminar
SUMMARY:Approximate actions and Ulam stability - Oren Beck
er (University of Cambridge)
DTSTART;TZID=Europe/London:20191108T134500
DTEND;TZID=Europe/London:20191108T144500
UID:TALK134194AThttp://talks.cam.ac.uk
URL:http://talks.cam.ac.uk/talk/index/134194
DESCRIPTION:Given two permutations A and B in Sym(n) such that
AB and BA are almost equal\, are there A' and B'
in Sym(n) such that A is close to A'\, B is close
to B'\, and A'B'=B'A'?\nArzhantseva and Paunescu f
ormalized this question and gave an affirmative an
swer: "Nearly commuting permutations are near comm
uting permutations". Equivalently\, approximate ac
tions of the group Z^2^ on finite sets are close t
o genuine actions\, i.e.\, Z^2^ is stable (in perm
utations).\nI will discuss the more general proble
m: Which finitely generated groups are stable?\n\n
This will bring into the picture notions such as P
roperty (T)\, amenability\, invariant random subgr
oups\, sofic groups and property testing.\n\nThe t
alk is based on joint works with Alex Lubotzky\, A
ndreas Thom and Jonathan Mosheiff.
LOCATION:CMS\, MR13
CONTACT:
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