NTNU Norwegian University of Science and Technology

Wed 26 Oct 2016, 3:15pm
Topology and related seminars
ESB 4133 (PIMS Lounge)

Freaks of algebra  a topologist's exhibition

ESB 4133 (PIMS Lounge)
Wed 26 Oct 2016, 3:15pm4:15pm
Abstract
For this survey talk I will bring a bestiary of algebraic structures that are often less well known than they deserve to be. As I will explain, these are all related to symmetries and topology, and they have interesting symmetries of their own. This observation leads to new homology computations, and those will be the results that I will present along the way. Part of this work is joint with N. Wahl.
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McGill

Fri 28 Oct 2016, 11:10am
SPECIAL
Topology and related seminars
ESB 4133 (PIMS Lounge)

Nonpositive Immersions and Counting Cycles

ESB 4133 (PIMS Lounge)
Fri 28 Oct 2016, 11:10am12:10pm
Abstract
The "nonpositive immersion" property is a condition on a 2complex X that generalizes being a surface. When X has this property, its fundamental group appears to have has some very nice properties which I will discuss. I will spend the remainder of the talk outlining a proof that the nonpositive immersion property holds for a 2complex obtained by attaching a single 2cell to a graph. This was proven recently with Joseph Helfer and also independently by Lars Louder and Henry Wilton.
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University of Washington

Wed 9 Nov 2016, 3:15pm
Topology and related seminars
ESB 4133 (PIMS Lounge)

Iterated Thom Spectra with Examples

ESB 4133 (PIMS Lounge)
Wed 9 Nov 2016, 3:15pm10:00am
Abstract
Given a fiber sequence of nfold loop spaces X>Y>Z, and morphism of nfold loop spaces Y>Pic(R) for R an E_{n+1}ring spectrum, we describe a method of producing a new morphism of (n1)fold loop spaces Z>Pic(MX), where MX is the Thom spectrum associated to the composition X>Y>Pic(R). This new morphism has associated Thom spectrum MY, but constructed directly as an MXmodule. In particular this induces a relative Thom isomorphism for MY over MX: MY⊗_{MX} MY = MY⊗Z. We will see a rough description of this construction as well as many examples allowing us to find equivalent forms of relative smash products of spectra like MString, MSpin, HZ/2, X(n) and many others. We also describe a way to use this construction to identify certain obstructions to giving a complex orientation on an associative ring spectrum.
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Reed College

Thu 10 Nov 2016, 3:15pm
SPECIAL
Topology and related seminars
ESB 4133 (PIMS Lounge)

The transfer map of free loop spaces

ESB 4133 (PIMS Lounge)
Thu 10 Nov 2016, 3:15pm4:15pm
Abstract
Associated to a fibration E > B with homotopy finite fiber is a stable wrong way map LB > LE of free loop spaces coming from the transfer map in THH. This transfer is defined under the same hypotheses as the BeckerGottlieb transfer, but on different objects. I will use duality in bicategories to explain why the THH transfer contains the BeckerGottlieb transfer as a direct summand. The corresponding result for the Atheory transfer may then be deduced as a corollary. When the fibration is a smooth fiber bundle, the same methods give a three step description of the THH transfer in terms of explicit geometry over the free loop space. (Joint work with C. Malkiewich)
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UBC

Wed 23 Nov 2016, 3:15pm
Topology and related seminars
ESB 4133 (PIMS Lounge)

TBA

ESB 4133 (PIMS Lounge)
Wed 23 Nov 2016, 3:15pm1:15am
Abstract
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