Photo of Lei Chen

Lei Chen



  • The universal surface bundle over the Torelli space has no sections. 2017.10
  • Section problems for configuration spaces of surfaces. 2017.08
  • Surjective homomorphisms between surface braid groups. 2017.04
  • The number of fiberings of a surface bundle over a surface. 2017.03. accepted by AGT
  • The universal n-pointed surface bundle only has n sections. 2016.11 to appear in Journal of Topology and Analysis.
  • Not for publication

    In Winter 2014 I passed my topic exam, on Characteristic Classes of Surface Bundles The proposal is here.


    Slides and videos

  • "No boundary" Farb Fest: Slides: Adding points to configurations. Video
  • ICMS Braid groups: Slides: Surjective homomorphisms between surface braid groups.
  • Oberwalfach surface bundle: Notes: The section problems Video
  • Schedule

  • 2018.1.16 Geometry and Topology seminar in Caltech
  • 2018.1.26 Geometry and Topology seminar in Columbia
  • 2018.2.8 Geometry and Topology seminar in Michigan
  • 2018.3.19 Geometry and Topology seminar in Peking University
  • 2018.4.2 Geometry and Topology seminar in Fudan
  • 2018.4.16 Geometry and Topology seminar in Maryland
  • Teaching

    Notes: more in my math blog

    Mapping Class Groups

  • Burau Representation PDF
  • Describe Johnson homomorphism using Massay Product PDF
  • Homology 3-sphere and Casson Invariant PDF
  • Torsions in mapping class group PDF
  • Birman-Hilden Theorem PDF
  • counting short geodesics on flat torus PDF
  • Earle-Eells Theorem PDF
  • Cohomology of Braid group with Z2 coefficient PDF
  • Random Topics

  • Finite generated residually finite group is Hopfian PDF
  • Grothendieck Riemann Roch PDF
  • polynomial growth--nilpotent group PDF
  • Reeb Stability Thurston PDF
  • Reading Groups

  • Reading group on moduli space Spring 2017 Website
  • About me

    I am a 5th year graduate student at the University of Chicago.
    I will be a postdoc at Caltech after September 2018.
    I study mapping class group, diffeomorphism group of surfaces and Teichmuller geometry.

    Postal address
    5734 S. University Avenue Eckhart 105
    Chicago, IL 60637-1514
    Advisor Benson Farb
    CV Here is my CV
    Blog Here is my math blog