The UC Berkeley combinatorics seminar
Spring 2021 - Monday 12:10pm - 1pm
Zoom Meeting ID is 929 2014 2787 Password is the name of our favorite combinatorial sequence
Organizers: Sylvie Corteel and Melissa Sherman-Bennett and Christopher Ryba

If you would like to speak or to be added to the seminar mailing list, contact Melissa Sherman-Bennett or Christopher Ryba.

DATE SPEAKER TITLE (click to show abstract)
January 25th Eugene Gorsky UC Davis
Algebraic weaves and braid varieties In the talk I will define braid varieties, a class of affine algebraic varieties associated to positive braids, and develop a Soergel-like diagrammatic calculus for correspondences between them. The braid varieties are closely related to augmentation varieties for Legendrian links, and the correspondences provide an algebraic machinery to study exact Lagrangian fillings of such links. This is a joint work with Roger Casals, Mikhail Gorsky and Jose Simental Rodriguez.
February 1st Christopher Ryba UC Berkeley
Stable characters from permutation patterns For a fixed permutation σ∈Sk, let Nσ denote the function which counts occurrences of σ as a pattern in permutations from Sn. We study the expected value (and d-th moments) of Nσ on conjugacy classes of Sn and prove that the irreducible character support of these class functions stabilizes as n grows. This says that there is a single polynomial in the variables n,m1,…,mdk which computes these moments on any conjugacy class (of cycle type 1^m1,2^m2,⋯) of any symmetric group. Our proof is, to our knowledge, the first application of partition algebras to the study of permutation patterns. This is joint work with Christian Gaetz.
February 8th Camille Combe Universite de Paris
February 15th Academic Holiday - no talk
February 22nd Nikhil Srivastava UC Berkeley
March 1st Jonathan Novak UCSD
March 8th Alejandro Morales UMass Amherst
March 15th Raul Penaguiao SFSU
March 22nd Spring Recess - no talk
March 29th Foster Tom UC Berkeley
April 5th Jeremy Meza UC Berkeley
April 12th Zajj Daugherty CUNY
April 19th Kelly Isham UC Irvine
April 26th Yulia Alexandr UC Berkeley
May 3rd Vasu Tewari University of Hawai'i
Older seminar webpages: Fall 2020 2018-2020 Spring 2018 Fall 2017 Spring 2017 Fall 2016