Past Seminar Talks

The following talks were given in past semesters.

Spring 2025

• May 8: Max Wiesmann, Arrangements and Likelihood

• May 15: Félix Gélinas, Source characterization of the hypegraphic posets

• May 22: No seminar on account of CanaDAM

• Tuesday May 27: Note Tuesday date on account of AlCoVE

  • 1:30pm: Elise Catania, A Toric Analogue for Greene’s Rational Function of a Poset

  • 2:30pm: Jesse Kim, Shifted Parking functions

• June 5: Alex Fink, The external activity complex of a pair of matroids

• June 12: Laura Pierson, Power sum expansions for the Kromatic symmetric function

• June 19: Elana Kalashnikov, The Abelian/non-Abelian correspondence and Littlewood-Richardson rules for two-step flags

• June 26: Leo Jiang, Oriented graded Möbius algebras

• July 3: Farhad Soltani, Quasisymmetric harmonics in superspace

• July 10: Karen Yeats, Sizes of witnesses in covtree

• July 17: Library archives visit

• July 24: No seminar on account of FPSAC

• July 31: URA day

  • 1:30pm: Kai Choi, Alice in Quadraticspanningforestidentityspace

  • 2:10pm: Peiran Tao, Algebraic Diagonals and Asymptotics of Bivariate Generating Functions

  • 2:50pm: Stephanie Penner, Combinatorial Exploration: Counting Chord Diagrams

• August 7 (12:00pm in MC 6029): Harper Niergarth, Reflected and Nonsymmetric Crystal Graphs

• August 7 (1:30pm): Tia Ruza, Multivariate Limit Theorems and Algebraic Generating Functions

Winter 2025

• January 16: Leigh Foster, The squish map and the SL2 double dimer model

• January 23: Karen Yeats, Combinatorial interpretation of the coefficients of the causal set theory d’Alembertian

• January 30: Nantel Bergeron, Equivariant quasisymmetry

• February 6: Hunter Spink, New perspectives on quasisymmetry via divided differences, flag varieties, etc.

• February 14 (postponed on account of snow): Yasaman Yazdi, Statistical Fluctuations in the Causal Set-Continuum Correspondence

• February 20: Reading week

• February 27: Katie Waddle, Spherical friezes

• March 6: Andrew Sack, Operahedron Lattices

• March 13: Stephen Melczer, Positivity of P-Recursive Sequences Satisfying Linear Recurrences

• March 20: Allen Knutson, Schubert calculus by counting puzzles

• March 27: Michael Borinsky, Asymptotic count of edge-bicolored graphs

• April 3: Harper Niergarth and Kartik Singh, The quasisymmetric Macdonald polynomials are quasi-Schur positive at $t = 0$

• April 10: Natasha Ter-Saakov, Log-concavity of random Radon partitions

Fall 2024

• September 12: Jerónimo Valencia, A combinatorial proof of an identity involving Eulerian numbers

• September 19: Karen Yeats, Tubings of rooted trees and resurgence

• September 26: Jonathan Leake, Approximately Counting Flows via Generating Function Optimization

• October 3: John Smith, Coefficient Positivity and Analytic Combinatorics

• October 10: Josh Swanson, Cyclotomic generating functions

• Tuesday October 15 (during reading week): Christian Gaetz, Hypercube decompositions and combinatorial invariance for Kazhdan-Lusztig polynomials

• October 24: Nick Olson-Harris, Sufficient conditions for equality of skew Schur functions

• October 31: Joseph Fluegemann, Smooth points on positroid varieties and planar $N=4$ supersymmetric Yang-Mills theory

• November 7: Stephan Pfannerer, Descents for Border Strip Tableaux

• November 14: Colleen Robichaux, Vanishing of Schubert coefficients

• November 21: Torin Greenwood, Coloring the integers while avoiding monochromatic arithmetic progressions

• November 28: Mike Cummings, Combinatorial rules for the geometry of Hessenberg varieties

• December 5: David Wagner, Valuable partial orders

Spring 2024

• May 16: Sarah Brauner, Configuration spaces and combinatorial algebras

• May 23: Li Yu, Integrable systems on the dual space of Lie algebras arising from log-canonical cluster structures

• May 30: Jette Gutzeit, Introducing the interval poset associahedron

• June 6: Tia Ruza, Central Limit Theorems via Analytic Combinatorics in Several Variables

• June 13: Karen Yeats, Chord diagrams, triangulations, and $\phi \rho$ amplitudes

• June 20: No seminar

• June 27: Paul Balduf, Combinatorial proof of a Non-Renormalization Theorem

• July 4: No seminar

• July 11: No seminar

• July 18: Laura Pierson, Two variations of the chromatic symmetric function Note: No preseminar this week

• July 25: no seminar on account of FPSAC

• August 1: URA day

  • 1pm: Connor Baetz, The ASEP and alternate multi-line queues

  • 1:30pm: coffee

  • 1:50pm: Arnav Kumar, Dimension of posets and random graph orders

  • 2:30pm: Ron Cherny, A Combinatorial Case of The Gerstenhaber Problem

• August 8: William Chan, Control over the Kerov-Kirillov-Reshetikhin bijection with respect to the nesting structure on rigged configurations

• August 15: Jang Soo Kim, Lecture hall graphs and the Askey scheme

Winter 2024

• January 25: Santiago Estupinan, A new shifted Littlewood-Richardson rule

• February 1: Arad Nasiri, Combinatorial Action in Causal Set Quantum Gravity

• February 8: Tim Miller, Vertex models for the product of a Schur and Demazure polynomial

• February 15: Karen Yeats, More Martin and $c_2$ details

• February 22: Reading week

• February 29: Leo Jiang, Real matroid Schubert varieties, zonotopes, and virtual Weyl group

• March 7: social time

• March 14: Nancy Wallace, Quasi-partition algebras representations, planar Quasi-partition algebras and Characters of the Motzkin-Riordan algebra

• March 21: Nathan Pagliaroli, Colored unstable map enumeration from random noncommutative geometries

• March 28: Harper Niergarth, On the faces of the Kunz cone and the numerical semigroups within them

• April 4: Olya Mandelshtam, A new formula for the symmetric Macdonald polynomials via the ASEP and TAZRP

• April 11: Alex Kroitor, Lattice Paths Through ACSV

• April 18: Jeremy Chizewer, Analytic Methods and Combinatorial Plants

Fall 2023

• September 14: Tianyi Yu, Analogue of Fomin-Stanley algebra on bumpless pipedreams

• September 21: Jeremy Chizewer, The Sunflower Problem: Restricted Intersections

• September 28: Kartik Singh, Closure of Deodhar components

• October 5: Karen Yeats, Diagrammatic boundary calculus for Wilson loop diagrams

• October 12: Reading week, no seminar

• October 19: Vasu Tewari, Forest polynomials and harmonics for the ideal of quasisymmetric polynomials

• October 26: David Wagner, Higher-order correlation inequalities for random spanning trees

• November 2: Jerónimo Valencia, Snake decompositions of lattice path matroids

• November 9: Spencer Daugherty, Extended Schur functions and bases related by involutions

• November 16: Alejandro Morales, Linear relations and Lorentzian property of chromatic symmetric functions

• November 23: Jason Bell, Filtered deformations of commutative algebras. Note, no pre-seminar this week

• November 30: Kelvin Chan, Polarization operators in superspace

Winter 2023

• January 12: Andy Wilson (Kennesaw State University), Coinvariants and superspace

• January 19: François Bergeron (LACIM), From the nabla operator to the super nabla operator

• January 26: Emily Barnard (De Paul University), Cluster combinatorics and poset topology

• February 2: Nick Olson-Harris (Waterloo), Binary tubings and Dyson-Schwinger equations

• February 9: Elana Kalashnikov (Waterloo), Quantum hooks and the Plücker coordinate mirror

• February 16: Stephen Gillen (Waterloo), Geometry of gradient flows for analytic combinatorics

• February 23: Reading week (no seminar)

• March 2: Social hour

• March 9: Joel Lewis (George Washington University), Bargain hunting in a Coxeter group

• March 16: Kartik Singh (Waterloo), Taking limits in Go-diagrams

• March 23: Lucas Gagnon (York University), Quasisymmetric varieties, excedances, and bases for the Temperley–Lieb algebra

• March 30: Freddy Cachazo (Perimeter), Arrangements of Pseudolines, Tropical Grassmannians, and Generalized Scattering Amplitudes