Department of

# Mathematics

Seminar Calendar
for events the day of Monday, April 27, 2015.

.
events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
      March 2015             April 2015              May 2015
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4  5  6  7             1  2  3  4                   1  2
8  9 10 11 12 13 14    5  6  7  8  9 10 11    3  4  5  6  7  8  9
15 16 17 18 19 20 21   12 13 14 15 16 17 18   10 11 12 13 14 15 16
22 23 24 25 26 27 28   19 20 21 22 23 24 25   17 18 19 20 21 22 23
29 30 31               26 27 28 29 30         24 25 26 27 28 29 30
31


Monday, April 27, 2015

12:00 pm in 341 AH,Monday, April 27, 2015

#### Prequantization of the moduli space of flat bundles on 2-manifolds with markings

###### Derek Krepski (U Manitoba)

Abstract: Let G be a compact Lie group and let S be an oriented 2-manifold. This talk discusses the obstruction to the existence of a prequantization (also called pre-quantum line bundle, a complex line bundle whose Chern class is the symplectic form) of the moduli space M of flat principal G-bundles over S (possibly with marked points and prescribed holonomies around those marked points). The moduli space M is placed in the framework of quasi-Hamiltonian group actions (with Lie group-valued moment maps), where there exists a compatible notion of prequantization expressed in terms of U(1)-gerbes (instead of line bundles). In this context, the obstruction can be described fully if G is simply connected; however if G is not simply connected, less is known.

3:00 pm in 243 Altgeld Hall,Monday, April 27, 2015

#### Homological algebra and rationality of varieties

###### Ian Shipman (Michigan)

Abstract: Going back to work of Bondal, Kawamata, Orlov, and others there are many compelling ways in which the homological algebra of an algebraic variety (more precisely, its derived category of coherent sheaves) reflects its birational geometry. I will explain joint work with Morgan Brown on a conjecture relating the structure of the derived category with rationality of a variety.

4:00 pm in 145 Altgeld Hall,Monday, April 27, 2015

#### Introduction to Cyclic Homology

###### Juan Villeta-Garcia (UIUC Math)

Abstract: We'll be giving a basic introduction to the ideas of Cyclic Homology, building up from Hochschild Homology, with a couple of examples. We'll be working from a letter of Goodwillie's to Waldhausen, and this (accessible) talk is meant mostly as an excuse for the speaker to work his way through the text.

5:00 pm in 241 Altgeld Hall,Monday, April 27, 2015

#### C*-algebras and Continued Fractions

###### Florin Boca (UIUC Math )

Abstract: The talk will discuss some connections between rotation C*-algebras, AF-algebras, and continued fractions.