# Events by month

## April 2022

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### Tutte Colloquium - Curtis Bright

Friday, April 1, 2022 — 3:30 PM EDT

Title: SAT Solving with Computer Algebra for Combinatorics

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.

### Algebraic Graph Theory Seminar - Nathan Lindzey

Tuesday, April 5, 2022 — 11:30 to 11:30 AM EDT

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.

### Graphs and Matroids Seminar - Lise Turner

Tuesday, April 5, 2022 — 3:00 PM EDT

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.

### Algebraic Combinatorics Seminar - Farid Aliniaeifard

Thursday, April 7, 2022 — 1:00 PM EDT

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.

### Algebraic Graph Theory Seminar - Victor Wang

Monday, April 11, 2022 — 11:30 to 11:30 AM EDT

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.

### Graphs and Matroids Seminar - Carolyn Chun

Tuesday, April 12, 2022 — 3:00 PM EDT

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.

### Reading Group Talk - Sean Kafer

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

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.

### Algebraic Combinatorics Seminar - Darij Grinberg

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

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

### Equity, Diversity, and Inclusion Panel

Tuesday, April 19, 2022 — 3:00 PM EDT

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.

### Cryptography Reading Group - Guiwen Luo

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

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.

### Algebraic Graph Theory Seminar - Mahsa N. Shirazi

Monday, April 25, 2022 — 11:30 to 11:30 AM EDT

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.

### ASA DataFest - Statistics and Actuarial Science

Friday, April 29, 2022 — 3:00 PM to Sunday, May 1, 2022 — 6:00 PM EDT to Sun, 05/01/2022 - 18:00

DataFest 2022 registration is now OPEN!

Register online now!

All members of your team must register.

### April 2022

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