Cohomology in algebra, geometry, physicsand statistics

On local and global invariants of flat bundles

Characteristic classes of flat bundles are related to the group cohomology of diffeomorphism groups.
But computing the group cohomology of these large groups as discrete groups is too complicated.
Even calculating the second cohomology of these groups will resolve deep problems in foliation theory.
However, it is easier to define certain natural cohomology classes (characteristic classes) in group
cohomology of diffeomorphism groups. We will discuss that they are rarely bounded classes but some
of them (e.g. Godbillon-Vey classes) are continuous cocycles. We will discuss some ways to detect their
nontriviality inspired by the work of Thurston and Bott-Segal.
--------------------------------------------------------------------------------------------
Please  notice the TIME  SHIFT   THIS  WEDNESDAY  ONLY.
We shall open the ZOOM meeting at 15.15 for virtual coffee
 Join Zoom Meeting
https://cesnet.zoom.us/j/99598413922?pwd=YXNFbk50aVhleXhWSGtISFViLytRUT09
MeetingID:99598413922
 Passcode:Galois