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DTSTART;TZID=America/New_York:20260925T100000
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DTSTAMP:20260922T143626Z
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SUMMARY:4-manifold topology and collision rank of groups
DESCRIPTION:Freedman Seminar \nSpeaker: Slava Krushkal (University of Virginia) \nTitle: 4-manifold topology and collision rank of groups \nAbstract: I will introduce collision rank and show that groups of finite collision rank are good in the sense of topological 4-manifold theory. Finitely generated groups of collision rank two are shown to exist outside the class of subexponentially amenable groups. I will describe examples given by commutator subgroups of topological full groups of Sturmian systems\, they include continuum many pairwise nonisomorphic infinite simple amenable groups.
URL:https://cmsa.fas.harvard.edu/event/freedman-seminar/
LOCATION:Virtual
CATEGORIES:Freedman Seminar
ATTACH;FMTTYPE=image/png:https://cmsa.fas.harvard.edu/media/2026/09/CMSA-Freedman-Seminar-9.25.26.docx-scaled.png
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