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Current Colloquia & Seminars

  1. Berkeley Topology Seminar: Part II: Main Talk - A variant of Rohlin's Theorem: on eta cubed

    Location: 3 Evans Hall
    Speakers: Michael Hill (University of Virginia)

    Rohlin's theorem on the signature of Spin 4-manifolds can be restated in terms of the connection between real and complex K-theory given by homotopy fixed points. This comes from a bordism result about Real manifolds versus unoriented manifolds, which in turn, comes from a C2-equivariant story. I'll describe a surprising analogue of this for
    larger cyclic 2 groups, showing that the element eta cubed is never detected! In particular, for any bordism theory orienting these generalizations of Real manifolds, the three torus is always a boundary.

    Created on Apr 17, 2014 04:55 PM PDT
  2. AT Research Seminar Pre-Talk: The Dold-Kan correspondence and commutative monoids

    Location: MSRI: Simons Auditorium
    Speakers: Birgit Richter (Universit├Ąt Hamburg)

    Over a field in characteristic zero commutative dgas are well-behaved; otherwise they are not. For instance there isn't a
    right-induced model structure on them in the general case. I'll explain some of these issues and advertise symmetric sequences to repair that defect.

    Updated on Apr 17, 2014 04:57 PM PDT
  3. AT Research Seminar: An algebraic model for commutative HZ-algebras.

    Location: MSRI: Simons Auditorium
    Speakers: Birgit Richter (Universit├Ąt Hamburg)

    Eilenberg-Mac Lane spectra represent singular cohomology and they allow for rather algebraic considerations in stable homotopy theory. Shipley proved that there is a Quillen equivalence between algebras over the Eilenberg-Mac Lane spectrum of the integers, HZ, and differential graded rings. I'll talk about ongoing work with her where we aim at extending her result to commutative HZ-algebras. This builds on a Dold-Kan type theorem for commutative monoids in symmetric sequences.

    Updated on Apr 23, 2014 09:24 AM PDT