Department of Mathematics

Geometry and Topology

  •  Justin Lanier, University of Chicago
  •  Mapping class groups and dense conjugacy classes
  •  11/29/2022
  •  3:00 PM - 4:00 PM
  •  Online (virtual meeting) (Virtual Meeting Link)
  •  Peter Kilgore Johnson (

I’ll start by introducing infinite-type surfaces—those with infinite genus or infinitely many punctures—and the emerging study of their mapping class groups. One difference from the finite-type setting is that these mapping class groups come with natural non-discrete topologies. I’ll discuss joint work with Nick Vlamis where we fully characterize which surfaces have mapping class groups with dense conjugacy classes, so that there exists an element that well approximates every mapping class, up to conjugacy.



Department of Mathematics
Michigan State University
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East Lansing, MI 48824

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College of Natural Science