Department of

# Mathematics

Seminar Calendar
for events the day of Wednesday, April 1, 2020.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
      March 2020             April 2020              May 2020
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


Wednesday, April 1, 2020

3:30 pm in https://illinois.zoom.us/j/806582029 (email Anush Tserunyan for the password),Wednesday, April 1, 2020

#### Random walks on graphs and spectral radius: part 2

###### Anush Tserunyan (UIUC Math)

Abstract: We will continue discussing random walks on graphs and their spectral radius, computing that the spectral radius of $\mathbb{Z}^d$ is $1$, whereas it is less than $1$ for a $d$-regular tree with $d \ge 3$. We will then discuss the deep and general theorem of Kesten characterizing amenable normal subgroups and derive a couple of striking corollaries: a characterization of finitely generated amenable groups and a rigidity result for the free groups.

4:00 pm in 245 Altgeld Hall,Wednesday, April 1, 2020

#### A family of number-theoretic directed graphs on the integers

###### Dana Neidinger

11:00 pm in Altgeld Hall,Wednesday, April 1, 2020