Department of

# Mathematics

Seminar Calendar
for events the day of Monday, January 27, 2014.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
    December 2013           January 2014          February 2014
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
8  9 10 11 12 13 14    5  6  7  8  9 10 11    2  3  4  5  6  7  8
15 16 17 18 19 20 21   12 13 14 15 16 17 18    9 10 11 12 13 14 15
22 23 24 25 26 27 28   19 20 21 22 23 24 25   16 17 18 19 20 21 22
29 30 31               26 27 28 29 30 31      23 24 25 26 27 28



Monday, January 27, 2014

2:00 pm in 147 Altgeld Hall,Monday, January 27, 2014

#### Reidemeister Torsion and Combinatorial Vector Fields

###### Mark Schubel (UIUC Physics)

Abstract: We discuss the relationship between Reidemeister torsion and combinatorial vector fields and their flows. We begin by introducing the twisted chain complex and defining Reidemeister torsion and proving some basic properties. We will use this to show that the Reidemeister torsion of a space can be written as the product of the torsion each of the basic sets.

4:00 pm in 245 Altgeld Hall,Monday, January 27, 2014

#### Isoperimetric Inequality and Q-curvature

###### Yi Wang (Stanford University)

Abstract: A well-known question in differential geometry is to prove the isoperimetric inequality under intrinsic curvature conditions. In dimension 2, the isoperimetric inequality is controlled by the integral of the positive part of the Gaussian curvature. In my recent work, I prove that on simply connected conformally flat manifolds of higher dimensions, the role of the Gaussian curvature can be replaced by the Branson's Q-curvature. The isoperimetric inequality is valid if the integral of the Q-curvature is below a sharp threshold. Moreover, the isoperimetric constant depends only on the integrals of the Q-curvature. The proof relies on the theory of $A_p$ weights in harmonic analysis.

5:00 pm in 241 Altgeld,Monday, January 27, 2014