The Applied Algebra Seminar

A
Monday afternoon research seminar

During 2023-24, the seminar is

IN PERSONat 15:00-16:00 EDT (GMT -4).

The seminar room is Ross Building room N638. If you come by public transportation, there is a York University subway station on the TTC Line 1 Yonge-Univerity route. If you come by car, you can find the available parking lots here.

The seminar has been running since 1997. The topics of talks have typically been any mixture of algebra with any other field: combinatorics, geometry, topology, physics, etc. Further down this page you will find links to the seminar webpages for previous years. The audience usually consists of 6–12 people, including several graduate students and post-docs. For this reason, speakers are encouraged to devote a portion of their talk to the suggestion of open problems and the directions for research in their area. If you are interested in speaking at the seminar, contact the organizers.

You may also be interested in the Algebraic Combinatorics Seminar at the Fields Institute.

The seminar is currently organized by Lucas Gagnon and Nantel Bergeron.

Dates are listed in reverse-chronological order. Unless otherwise indicated, all in person talks will take place on Monday from 15:00-16:00 in N638 Ross Building (York University).

Date Speaker Title (click titles for abstract) 16 Dec. 2024 Seeking Speaker!

TBA9 Dec. 2024 Seeking Speaker!

2 Dec. 2024 Seeking Speaker!

TBA25 Nov. 2024

Ravali Nookala

TBA18 Nov. 2024 Karen Yeats

U. Waterloo TBA11 Nov. 2024

Seeking Speaker!

TBA4 Nov. 2024 Seeking Speaker!

TBA28 Oct. 2024

Aaron Lauve

Loyola Chicago TBA21 Oct. 2024 Lucas Gagnon

York TBAReading Week7 Oct. 2024 Jerónimo Valencia

U. WaterlooA combinatorial proof of an identity involving Eulerian numbers In 2009, Brenti and Welker studied the Veronese construction for formal power series which was motivated by the corresponding construction for graded algebras. As a corollary of their algebraic computations, they discovered an identity for the coefficients of the Eulerian polynomials. The authors asked for a combinatorial proof of this identity given that all of its ingredients are enumerative in nature. In this talk I will present one such combinatorial proof.30 Sept. 2024 Nantel Bergeron

YorkA quantum Murnaghan--Nakayama rule for the flag manifold Based on joint work with Benedetti, Colmenarejo, Saliola, and Sottile (arxiv:2406.053311). We give a rule for the multiplication of a Schubert class by a tautological class in the (small) quantum cohomology ring of the flag manifold. As an intermediate step, we establish a formula for the multiplication of a Schubert class by a quantum Schur polynomial indexed by a hook partition. This entails a detailed analysis of chains and intervals in the quantum Bruhat order. This analysis allows us to use results of Leung--Li and of Postnikov to reduce quantum products by hook Schur polynomials to the (known) classical product.23 Sept. 2024 Hugh Thomas

UQAMCyclic actions on noncrossing and nonnesting partitions Noncrossing partitions and nonnesting partitions are both counted by Catalan numbers. Noncrossing partitions on [n] admit a natural cyclic action of order 2n, induced by the Kreweras complement. Nonnesting partitions admit a natural toggle-based action; in fact, they admit one such action for each choice of Coxeter element of the symmetric group. We prove that the latter actions all have order 2n by constructing a family of bijections between noncrossing and nonnesting partitions, equivariant with respect to the cyclic actions on either side. This talk is based on arXiv:2212.14831, joint with Benjamin Dequêne, Gabriel Frieden, Alessandro Iraci, Florian Schreier-Aigner, and Nathan Williams. Our results were presented at FPSAC in July; our extended abstract (and Nathan's slides) are available from the FPSAC website.

Below you will find links to the seminar webpages for previous years.