Monday Analysis Seminar: Ktheory for operator algebras and Bass–Serre theory
 Date

2015114 16:30 
2015114 18:00
 Place
 Faculty of Science Buliding #3 Room 210

Speaker/Organizer
 Kei Hasegawa (Kyushu University)

 A C*algebra is a ``selfadjoint'' algebra of bounded linear operators on a Hilbert space which is closed in the norm topology. In this seminar, I will talk about the problem that, for given C*algebras A and B, how can we compute the Ktheory of their (amalgamated) free products from those of A and B for nonspecialists.
In the first half of the seminar, I review the historical background of the problem since 1970s, introducing two concrete C*algebras: the C*algebra associated with the free group of rank 2 and the noncommutative tori.
In the second half of the seminar, I talk about Ktheory of C*algebras associated with amalgamated free products of discrete groups. Here, the notion of amenability and BassSerre theory play important roles. Finally, I will explain my recent result on Ktheory of amalgamated free products of general C*algebras.
Different time and day of the week.