Department of

# Mathematics

Seminar Calendar
for events the day of Thursday, December 5, 2019.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
    November 2019          December 2019           January 2020
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2    1  2  3  4  5  6  7             1  2  3  4
3  4  5  6  7  8  9    8  9 10 11 12 13 14    5  6  7  8  9 10 11
10 11 12 13 14 15 16   15 16 17 18 19 20 21   12 13 14 15 16 17 18
17 18 19 20 21 22 23   22 23 24 25 26 27 28   19 20 21 22 23 24 25
24 25 26 27 28 29 30   29 30 31               26 27 28 29 30 31



Thursday, December 5, 2019

11:00 am in 241 Altgeld Hall,Thursday, December 5, 2019

#### Fourth Moments of Modular Forms on Arithmetic Surfaces

###### Ilya Khayutin (Northwestern University)

Abstract: I will describe a method to study the fourth moment of periods of Hecke eigenforms using a second moment pre-trace formula. The second moment pre-trace formula is constructed out of the usual pre-trace formula using non-standard test functions involving all Hecke operators. It can also be understood using the theta correspondence. Our main application is to the sup-norm problem for modular forms on arithmetic surfaces. Joint work with Raphael Steiner.

12:00 pm in 243 Altgeld Hall,Thursday, December 5, 2019

#### Universal circles and Cannon-Thurston maps

###### Steven Frankel (Washington University in St Louis)

Abstract: The coarse dynamics of a quasigeodesic or pseudo-Anosov flow is captured by a topological circle, lying at infinity, equipped with an action of the ambient manifold's fundamental group. We will discuss how these "universal circles" interleave the dynamics of the flow with the geometry of the ambient manifold.

3:00 pm in 347 Altgeld Hall,Thursday, December 5, 2019

#### Maximizing the Edelman-Greene statistic

###### Gidon Orelowitz   [email] (UIUC)

Abstract: The Edelman-Greene statistic of of S. Billey-B. Pawlowski measures the "shortness" of the Schur expansion of a Stanley symmetric function. We show that the maximum value of this statistic on permutations of Coxeter length $n$ is the number of involutions in the symmetric group $S_n$ and explicitly describe the permutations that attain this maximum. Our proof confirms a recent conjecture of C. Monical, B. Pankow, and A. Yong: we give an explicit combinatorial injection between a certain collections of Edelman-Greene tableaux and standard Young tableaux.

4:00 pm in 314 Altgeld Hall,Thursday, December 5, 2019

#### IT issues

###### Computer Steering Committee and Math IT Group (Illinois Math)

Abstract: The Chair, the Computer Steering Committee (CCOM) and the Math IT Group invites you to a departmental meeting of all faculty and staff to discuss the possible implementation of CrowdStrike antivirus/antimalware/antiransom software on all departmental computers. About a month ago the IT group informed CCOM about this possibility and it was promptly discussed in a committee meeting which included two campus IT security specialists. The meeting revealed both the capabilities of this new type of antivirus and the privacy concerns it raises. The CCOM thought that these concerns should be brought to the attention of all faculty and staff in the department. We waited to see whether the campus wide, Town Hall meeting on this subject, held on Nov. 21, would accomplish the same goal but we learned that it was not well attended and was much less informative than we would have liked it to be. Therefore, we invite you to learn about and discuss the benefits and drawbacks of the CrowdStrike antivirus. Your feedback is essential for the department to have a strong voice on whether it should be implemented and with what restrictions.