A human property (T) proof for high-rank Aut(F_n)

  • Tagungsort:

    Geb 20.30, SR 2.058

  • Datum:


  • Referent:

    Martin Nitsche

  • Zeit:

    15:45 Uhr

  • Abstract: Kazhdan's property (T) is an important rigidity property for groups. Typically, it is difficult to show that a given group satisfies property (T), and the proof that the automorphism groups of the free groups, Aut(Fn), have property (T) for n>=4 is an important result of recent years.

    These proofs rely crucially on extensive computer calculations. We give a new proof that Aut(Fn) has property (T) for all but finitely many n that is inspired by the semidefinite programming approach but does not use the computer in any step. More specifically, we prove property (T) for a certain extension Γn of SAut(Fn) as n goes to infinity.