[Turkmath:907] Two talks at the MSGSU this Thursday : Mehmet Akif Erdal and Burak Kaya

[Mohan Ravichandran]

Dear All,

   Mehmet Akif Erdal from Bilkent and Burak Kaya from Rutgers will
speak this Thursday at the MSGSU mathematics seminar.

Speaker : Mehmet Akif Erdal, Bilkent
Time : 16:00, Thursday, December 24

Title: Homology and cohomology theories graded over monoidal categories

Abstract: This talk is based on a joint work with Özgün Ünlü. I will
first discuss the monoid actions on sets, which is via action from
both sides, but different then the usual biactions in terms of
equivariance of maps. Using this view point, we will be able to
associate a new action to a given monoid action on a set, so called
inverse action, which generalizes the notion of inverse of group
actions. In the second part I will discuss categorification of these
definitions. I will define action of a monoidal categories on a
category and the inverse of such action, analogues to the monoid case.
As an application, "homology and cohomology theories graded over a
monoidal category" will be introduced, which generalizes the usual
definitions of (co)homology and (co)homotopy theories existing in the
literature. This allow us to view (co)homology and (co)homotopy
theories as fixed points of an action of monoidal category on a
category.


Speaker : Burak Kaya, Rutgers
Time : 17:00, Thursday, December 24

Title: The complexity of topological conjugacy of pointed Cantor minimal systems

Abstract: In this talk, we analyze the complexity of the topological
conjugacy relation on Cantor minimal systems from the point of view of
descriptive set theory. We shall show that topological conjugacy of
pointed Cantor minimal systems is Borel bireducible with the equality
of countable sets of reals. We will also show that this is a lower
bound for the Borel complexity of topological conjugacy of Cantor
minimal systems. If time permits, we will cover some applications of
our results to properly ordered Bratteli diagrams.

Warm regards,
Mohan