Department of

# Mathematics

Seminar Calendar
for events the day of Tuesday, February 7, 2017.

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events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
     January 2017          February 2017            March 2017
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  3  4
8  9 10 11 12 13 14    5  6  7  8  9 10 11    5  6  7  8  9 10 11
15 16 17 18 19 20 21   12 13 14 15 16 17 18   12 13 14 15 16 17 18
22 23 24 25 26 27 28   19 20 21 22 23 24 25   19 20 21 22 23 24 25
29 30 31               26 27 28               26 27 28 29 30 31



Tuesday, February 7, 2017

12:00 pm in 243 Altgeld Hall,Tuesday, February 7, 2017

#### The generation problem in Thompson group F

###### Gili Golan (Vanderbilt)

Abstract: We show that the generation problem in Thompson group F is decidable, i.e., there is an algorithm which decides if a finite set of elements of F generates the whole F. The algorithm makes use of the Stallings 2-core of subgroups of F, which can be defined in an analogue way to the Stallings core of subgroups of a free group. An application of the algorithm shows that F is a cyclic extension of a group K which has a maximal elementary amenable subgroup B. The group B is a copy of a subgroup of F constructed by Brin and Navas.

1:00 pm in 345 Altgeld Hall,Tuesday, February 7, 2017

#### Canceled

3:00 pm in 241 Altgeld Hall,Tuesday, February 7, 2017

#### The maximum number of cliques in graphs without long cycles

###### Ruth Luo (Illinois Math)

Abstract: The Erdős-Gallai Theorem states that for $k\geq 3$ every graph on $n$ vertices with more than $\frac{1}{2}(k-1)(n-1)$ edges contains a cycle of length at least $k$. Kopylov proved a strengthening of this result for 2-connected graphs with extremal examples $H_{n,k,t}$ and $H_{n,k,2}$. In this talk, we generalize the result of Kopylov to bound the number of $s$-cliques in a graph with circumference less than $k$. Furthermore, we show that the same extremal examples that maximize the number of edges also maximize the number of cliques of any fixed size. Finally, we obtain the extremal number of $s$-cliques in a graph with no path on $k$-vertices.

4:00 pm in 245 Altgeld Hall,Tuesday, February 7, 2017

#### From Altgeld Hall to Data Science in Industry

###### Christopher Bonnell and Austin Rochford   [email] (Monetate, Inc.)

Abstract: In this informal discussion conducted by Skype, the panelists from Monetate will describe their career paths from our Mathematics graduate program into data science in industry, and then take questions from the audience. All are welcome to participate in this career event! Chris Bonnell received his PhD from our Department in 2013 (advised by Lee DeVille), and Austin Rochford got his MS here in 2009 (working in functional analysis).