# Events - April 2022

Friday, April 29, 2022 — 3:00 PM to Sunday, May 1, 2022 — 6:00 PM EDT

## ASA DataFest - Statistics and Actuarial Science

DataFest 2022 registration is now OPEN!

Register online now!

All members of your team must register.

Monday, April 25, 2022 — 11:30 AM EDT

## Algebraic Graph Theory Seminar - Mahsa N. Shirazi

Title: On the eigenvalues of the perfect matching derangement graph

 Speaker: Mahsa N. Shirazi Affiliation: University of Regina Zoom: Contact Sabrina Lato for link

Abstract:

The perfect matching derangement graph $M_{2n}$ is defined to be the graph whose vertices are all the perfect matchings of the complete graph $K_{2n}$, and two vertices are adjacent if they contain no common edges. The graph $M_{2n}$ is part of a larger study on the analogs of the Erdős-Ko-Rado theorem, and recently there have been interesting works on $M_{2n}$ and its eigenvalues.

Thursday, April 21, 2022 — 11:30 AM EDT

## Cryptography Reading Group - Guiwen Luo

Title: Speeding up Multi-Scalar Multiplication over Fixed Points towards Efficient zkSNARKs

 Speaker: Guiwen Luo Affiliation: University of Waterloo Attend: Contact Jesse Elliott

Abstract:

The arithmetic of computing multiple scalar multiplications in an elliptic curve group then adding them together is called multi-scalar multiplication (MSM). MSM over fixed points dominates the time consumption in pairing-based trusted setup zero-knowledge succinct non-interactive arguments of knowledge (zkSNARKs), thus fast algorithms of MSM over fixed points are desirable for practical applications.

Tuesday, April 19, 2022 — 3:00 PM EDT

## Equity, Diversity, and Inclusion Panel

Join us for a panel discussion focused on understanding and promoting equity, diversity, and inclusion (EDI) in academic settings. All members of our academic communities should strive to create equitable, diverse, and inclusive environments.

Thursday, April 14, 2022 — 1:00 PM EDT

## Algebraic Combinatorics Seminar - Darij Grinberg

Title: The one-sided cycle shuffles in the symmetric group algebra

 Speaker: Darij Grinberg Affiliation: Drexel University Zoom: Contact Logan Crew or Olya Mandelshtam

Abstract:

Elements in the group algebra of a symmetric group S_n are known to have an interpretation in terms of card shuffling. I will discuss a new family of such elements, recently constructed by Nadia Lafrenière: Given a positive integer n, we define n elements t_1, t_2, ..., t_n in

Wednesday, April 13, 2022 — 2:00 PM EDT

## Reading Group Talk - Sean Kafer

Title: Generating Short Monotone Paths in 0/1 LPs: From Circuits to Simplex

 Speaker: Sean Kafer Affiliation: University of Waterloo Zoom: 945 0789 9910 (passcode: kafer)

Abstract:

Even after decades of study, it is unknown whether there exists a pivot rule for the Simplex method that always solves an LP with only a polynomial number of pivots.  This remains unknown even in the special case of 0/1 LPs - i.e., LPs defined over 0/1 polytopes - a case that includes many extensively studied problems in combinatorial optimization.

Tuesday, April 12, 2022 — 3:00 PM EDT

## Graphs and Matroids Seminar - Carolyn Chun

Title: Lattice path matroids, lattice path polymatroids, and excluded minors

 Speaker: Carolyn Chun Affiliation: US Naval Academy Zoom: http://matroidunion.org/?page_id=2477 or contact Shayla Redlin

Abstract:

We define lattice path matroids, polymatroids, Boolean polymatroids, and lattice path polymatroids, which are a subclass of Boolean polymatroids.

Monday, April 11, 2022 — 11:30 AM EDT

## Algebraic Graph Theory Seminar - Victor Wang

Title: Deletion-contraction for a unified Laplacian and applications

 Speaker: Victor Wang Affiliation: University of British Columbia Zoom: Contact Sabrina Lato

Abstract:

We define a graph Laplacian with vertex weights in addition to the more classical edge weights, which unifies the combinatorial Laplacian and the normalised Laplacian.

Thursday, April 7, 2022 — 1:00 PM EDT

## Algebraic Combinatorics Seminar - Farid Aliniaeifard

Title: Modular relations between chromatic symmetric functions

 Speaker: Farid Aliniaeifard Affiliation: University of British Columbia Zoom: Contact Logan Crew or Olya Mandelshtam

Abstract:

In 1995, Stanley introduced the chromatic symmetric functions. The study of chromatic symmetric functions of graphs inspired two main research directions.

Tuesday, April 5, 2022 — 3:00 PM EDT

## Graphs and Matroids Seminar - Lise Turner

Title: A local version of Hadwiger’s Conjecture

 Speaker: Lise Turner Affiliation: University of Waterloo Zoom: http://matroidunion.org/?page_id=2477 or contact Shayla Redlin

Abstract:

In 1943, Hadwiger famously conjectured that graphs with no $K_t$ minors are $t-1$ colourable. There has also been significant interest in several variants of the problem, such as list colouring or only forbidding certain classes of minors.

Tuesday, April 5, 2022 — 11:30 AM EDT

## Algebraic Graph Theory Seminar - Nathan Lindzey

Title: Yet Another Proof of the Erdős-Ko-Rado Theorem

 Speaker: Nathan Lindzey Affiliation: University of Colorado, Boulder Zoom: Contact Sabrina Lato

Abstract:

We give a short new algebraic proof of the Erdős-Ko-Rado theorem, that for k < n/2, the largest families of k-sets of an n-element set such that any two of its members intersect are precisely those families composed of all k-sets that contain some fixed element.

Friday, April 1, 2022 — 3:30 PM EDT

## Tutte Colloquium - Curtis Bright

Title: SAT Solving with Computer Algebra for Combinatorics

 Speaker: Curtis Bright Affiliation: University of Windsor and Carleton University Location: MC 5501 or please contact Emma Watson for Zoom link

Abstract:

This talk will describe a method of solving combinatorial problems by coupling Boolean satisfiability (SAT) solvers with computer algebra systems (CASs), thereby combining the search and learning power of SAT solvers with the expressiveness and mathematical sophistication of CASs.

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