May 24th, 2022

  • Date:


  • Speaker:

    Sam Hughes (University of Oxford)



    Irreducible lattices fibring over the circle



    Let n≥2 and let Λ be a lattice in a product of simple non-compact Lie groups with finite centre. An application of the Margulis Normal Subgroup Theorem implies that if H1(Λ) is non-zero, then Λ is reducible. In the more general CAT(0) setting there are many irreducible lattices with non-vanishing first cohomology. In this case we can deploy the BNSR invariants and investigate how far these cohomology classes are from a fibration of finite type CW complexes. In this talk we will combine the groups of Leary and Minasyan with the technology of Bestvina and Brady to construct the first examples of irreducible lattices which fibre over the circle.



    10:00 - 11:30 RTG Lecture 1 (Max Riestenberg), SR 2.058

    11:30 - 12:00 Get-Together with speaker, SR2.058

    12:00 - 13:00 Common lunch

    13:00 - 13:30 Informal meeting of PhD students, Topologischer Raum

    13:45 - 14:45 RTG colloquium: Sam Hughes, SR. 1067

    14:45 - 15:30 Common tea, Faculty meeting room 1.058

    15:30 - 17:00 RTG Lecture 3 (Alexander Lytchak), SR 1.067

  • Place: