BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4//
BEGIN:VEVENT
UID:20260427T033144EDT-19883MNv7d@132.216.98.100
DTSTAMP:20260427T073144Z
DESCRIPTION:COLLOQUE DES SCIENCES MATHÉMATIQUES DU QUÉBEC\n\nTitle: Orbit e
 quivalence relations and the compact action realization problem\n\nAbstrac
 t: The study of orbit equivalence relations induced by Borel actions of co
 untable groups on Polish (separable completely metrizable) spaces\, and th
 eir orbit spaces\, has been a very active area of research for several dec
 ades in various fields of mathematics\, including ergodic theory\, operato
 r algebras\, geometric group theory\, combinatorics\, probability and desc
 riptive set theory. Many results in this area have been obtained using erg
 odic (measure theoretic) methods. After giving a basic introduction to thi
 s theory\, I will focus on a new direction of topological nature that deal
 s with the problem of realizing orbit equivalence relations by continuous 
 actions on compact metrizable spaces and in particular subshifts. This als
 o leads to considering a natural universal space for such actions and equi
 valence relations via subshifts and originates the study in this space of 
 various important classes\, especially the so-called hyperfinite ones\, wh
 ich are those induced by actions of the group of integers. This is joint w
 ork with Josh Frisch\, Forte Shinko and Zoltan Vidnyánszky.\n\nLocation : 
 CRM\, Pavillon André Aisenstadt\, Room 5340\n\n \n
DTSTART:20260407T151500Z
DTEND:20260407T151500Z
SUMMARY:Alexander Kechris (Caltech)
URL:/mathstat/channels/event/alexander-kechris-caltech
 -372290
END:VEVENT
END:VCALENDAR