Feb. 12
3:154:15 in LD 027 (Note room change)

Ellen Weld (Purdue, West Lafayette)
Connectivity of Bieberbach Group C^{*}algebras
Abstract [+]
C^{*}algebras are involutive Banach algebras satisfying the C^{*} condition and generalize commutative topological spaces to noncommutative spaces which still have topological properties. One such property of interest is connectivity, which relates the C^{*}algebra to a topological invariant called Ktheory. In this talk, we will discuss connectivity related specifically to C^{*}algebras which arise from Bieberbach groups, themselves interesting as fundamental groups of compact Riemannian flat manifolds. We will discuss the intimate relationship between the unitary dual of these groups and the spectrum of their C^{*}algebras in addition to addressing obstructions to connectivity.

Mar. 5
9:3010:30am, LD 265
Joint with the Geometry Seminar

Jun Li (U. Michigan)
The symplectomorphism groups of rational 4manifolds
Abstract 
Mar. 28
3:154:15 (Note: Thursday talk)

Bernardo Villarreal (UNAM, Mexico City)
Affine commutativity
Abstract [+]
In this talk I'll define a model for the homotopy fiber, E_{com}G, of the inclusion of the classifying space for commutativity, B_{com}G into the classifying space BG. Simplicially, this model consists of n tuples of G where the quotients (meaning gh^{1}) commute. With this model, we can define a map E_{com}G  > B[G,G]. An interesting application is that one can easily show that a discrete group G is abelian if and only if the fundamental group of E_{com}G is trivial.
This is an ongoing project with O. AntolínCamarena.

April 9
3:154:15

Jake Desmond (Purdue, West Lafayette)
Extensions of Quasidagonal C*algebras
Abstract [+]
The equivalence of Quasidiagonal and stably finite C*algebras has long been studied. While in general they are not equivalent, the question is still open when restricted to the nuclear case. This work will examine their relationship in the setting of extensions of C*algebras and the Ktheoretical properties that occur.

April 23
3:154:15 in LD 030 (Note room change)

Chris Neuffer (IUPUI)
Cohomology of semidirect product groups
Abstract [+]
We will begin with a review of some basic concepts and examples from
group cohomology. Then we will consider Brady's notion of compatible
actions, which can be used to build free resolutions over semidirect
products. Recent work of Adem et al. has applied these ideas to obtain
new results about cohomology of crystallographic groups.

Past semesters:
Fall 2018
Spring 2018
Fall 2017
Spring 2017
Fall
2016

IUPUI • Department of
Mathematical Sciences 