BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20251220T153456EST-9295PnIMVS@132.216.98.100 DTSTAMP:20251220T203456Z DESCRIPTION: \n\nTitle: An ergodic advertisement for descriptive graph comb inatorics\n\nAbstract\n\nDating back to Birkhoff\, pointwise ergodic theor ems for probability measure preserving (pmp) actions of countable groups a re bridges between the global condition of ergodicity (measure-transitivit y) and the local combinatorics of the actions. Each such action induces a Borel equivalence relation with countable classes and the study of these e quivalence relations is a flourishing subject in modern descriptive set th eory. Such an equivalence relation can also be viewed as the connectedness relation of a locally countable Borel graph. These strong connections bet ween equivalence relations\, group actions\, and graphs create an extremel y fruitful interplay between descriptive set theory\, ergodic theory\, mea sured group theory\, probability theory\, and descriptive graph combinator ics. I will discuss how descriptive set theoretic thinking combined with c ombinatorial and measure theoretic arguments yields a pointwise ergodic th eorem for quasi-pmp locally countable graphs. This theorem is a vastly gen eral random version of pointwise ergodic theorems for group actions and is provably the best possible pointwise ergodic result for some of these act ions.\n\n \n\n \n DTSTART:20181213T210000Z DTEND:20181213T220000Z LOCATION:Room 1104\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Anush Tserunyan - Urbana-Champaign URL:/mathstat/channels/event/anush-tserunyan-urbana-ch ampaign-292391 END:VEVENT END:VCALENDAR