Department of

# Mathematics

Seminar Calendar
for events the day of Friday, September 5, 2014.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
     August 2014           September 2014          October 2014
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1  2       1  2  3  4  5  6             1  2  3  4
3  4  5  6  7  8  9    7  8  9 10 11 12 13    5  6  7  8  9 10 11
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Friday, September 5, 2014

3:00 pm in 245 Altgeld Hall,Friday, September 5, 2014

#### Information Session

###### Richard Laugesen, Director of Graduate Studies in Mathematics   [email] (UIUC Math)

Abstract: Information session for undergraduates interested in applying to Mathematics graduate programs in the United States. (Not specific to U of Illinois.) Come and ask about GREs, TOEFL, personal statements, letters of recommendation, public vs. private universities, and more.

4:00 pm in 343 Altgeld Hall,Friday, September 5, 2014

#### Genomic Tableaux and Equivariant K-Theory of Grassmannians

###### Oliver Pechenik   [email] (UIUC Math)

Abstract: The cohomology of a complex Grassmannian is well-known to be isomorphic to a certain ring of symmetric functions. More specifically, intersecting Schubert varieties on the Grassmannian corresponds to multiplying certain Schur polynomials. The ring structures are governed by the Littlewood-Richardson coefficients, which are computed in a manifestly positive fashion by various techniques, including the use of certain Young tableaux. We extend the relevant tableau combinatorics yielding a new positive rule for the analogous questions with Grothendieck polynomials as well as the first positive rule (proof in progress) for double Grothendieck polynomials. These correspond respectively to the K-theory and T-equivariant K-theory rings of the Grassmannian. (Joint with Alexander Yong.)

4:00 pm in 243 Altgeld Hall,Friday, September 5, 2014

#### Alexandrov meets Lorentz

###### Bill Karr (UIUC Math)

Abstract: Lorentzian manifolds are the mathematical objects that model the universe in general relativity theory. Alexandrov geometry is the study of metric spaces with curvature bounds. In this talk we will introduce some basic concepts from Lorentzian geometry and Alexandrov geometry. Then we will discuss recent efforts to use methods from Alexandrov geometry to study Lorentzian manifolds.

4:00 pm in 345 Altgeld Hall,Friday, September 5, 2014

#### Szemeredi's Lemma for the Analyst

###### Erik Walsberg (UCLA/UIUC)

Abstract: I will discuss Szemeredi Regularity, an analytic analogue of Szemeredi Regularity and the theory of limits of sequences of finite graphs. This is the first talk in a series the paper "Szemeredi's Lemma for the Analyst" by Lovasz-Szegedy.