The UC Berkeley combinatorics seminar
Spring 2023 - Monday 4:10pm - 5pm
Zoom Meeting ID: 953 1714 3805, the password is the name of our favorite combinatorial sequence
Organizers: Andrés R. Vindas Meléndez and Christopher Ryba and Mitsuki Hanada and John Lentfer

If you would like to be added to the seminar mailing list, contact Andrés R. Vindas Meléndez or Christopher Ryba.

DATE SPEAKER TITLE (click to show abstract)
January 30th Max Wimberley, UC Berkeley
Introduction to the Schiffmann Algebra and its Applications Discovered by Schiffmann and Vasserot in 2008 as the Hall Algebra of an elliptic curve, the Schiffmann algebra has proven to be a remarkably useful tool in unifying and generalizing many topics in symmetric function theory, including the diagonal harmonics and the shuffle conjecture. My talk will focus on providing an accessible exposition of the algebra, its presentations and its symmetries, grounded in computation. As time allows, I will discuss my own investigation into a particular Poisson degeneration of the algebra and its relationship to a conjectured formula for the "triagonal harmonics," the version of the diagonal harmonics with three alphabets of variables instead of two.
Recording (passcode: rZ*PYT7T)
February 6th Tamsen McGinley, Santa Clara University
Crystals Graphs, Perforated Tableaux, and Combinatorial Objects Crystal graphs of biwords are directed graphs whose nodes are biwords and whose edges are determined by "crystal operators". These are used to model irreducible representations of GL_n . We present a new model for the nodes of a crystal graph, called a "perforated tableaux", on which the crystal operators are easily defined. We show that several well-known combinatorial objects, including semi-standard Young tableaux, Littlewood-Richardson fillings, and the Robinson-Schensted-Knuth correspondence, naturally appear in the setting of perforated tableaux.
Friday, February 10th, Evans 740, 4 PM Sarah Brauner, University of Minnesota
Configuration spaces and combinatorial algebras In this talk, I will discuss connections between configuration spaces, an important class of topological space, and combinatorial algebras arising from the theory of reflection groups. In particular, I will present work relating the cohomology rings of some classical configuration spaces—such as the space of n ordered points in Euclidean space—with Solomon’s descent algebra and the peak algebra. The talk will be centered around two questions. First, how are these objects related? Second, how can studying one inform the other? This is joint, on-going work with Marcelo Aguiar and Vic Reiner.
February 13th No Seminar
February 20th Academic Holiday - No Seminar
February 27th
March 6th
Tuesday March 7th, Evans 748, 4 PM Bruce Sagan, Michigan State University
March 13th Ray Li, UC Berkeley
March 20th Lucy Martinez, Rutgers University
March 27th Spring Break - No Seminar
April 3rd Yan Zhuang, Davidson College
April 10th Joseph Pappe, UC Davis
April 17th Dustin Ross, SFSU
April 24th Mark Haiman, UC Berkeley
May 1st Anastasia Chavez, St. Mary's College of CA
May 3rd, time and place TBA Matt Hogancamp, Northeastern University
Older seminar webpages: Fall 2022 Spring 2022 Fall 2021 Spring 2021 Fall 2020 2018-2020 Spring 2018 Fall 2017 Spring 2017 Fall 2016