Babytop

Student seminar in topology

Fall 2004






Tyler Lawson
Gamma Spaces

Abstract:

The category of $\Gamma$-spaces is a symmetric monoidal category used as a model for connective spectra. A $\Gamma$-space is a functor from the category of finite pointed sets to the category of pointed spaces which preserves the initial object. Many machines for constructing infinite loop spaces naturally take values in $\Gamma$-spaces, including those associated to topological abelian monoids, spaces with partially defined multiplication, modules over an $E_\infty$ operad, and various definitions of $K$-theory. We will go over the definitions, compare with other categories of spectra, construct the symmetric spectrum associated to a $\Gamma$-space, define the smash product of Lyadakis, and see some examples. Additionally, I will discuss a generalization to a $G$-equivariant context, where $G$ is a compact Lie group.