Combinatorics and Arithmetic for Physics

Collection Combinatorics and Arithmetic for Physics

Organizer(s) Gérard H.E. Duchamp, Maxim Kontsevich, Gleb Koshevoy and Hoang Ngoc Minh
Date(s) 02/12/2020 - 03/12/2020
linked URL https://indico.math.cnrs.fr/event/6181/
00:00:00 / 00:00:00
6 15

Quotients of Symmetric Polynomial Rings Deforming the Cohomology of the Grassmannian

By Darij Grinberg

One of the many connections between Grassmannians and combinatorics is cohomological: The cohomology ring of a Grassmannian $Gr(k,n)$ is a quotient of the ring $S$ of symmetric polynomials in k variables. More precisely, it is the quotient of $S$ by the ideal generated by the $k$ consecutive complete homogeneous symmetric polynomials $h_{n−k},h_{n−k+1},…,h_n$. We deform this quotient, by replacing the ideal by the ideal generated by $h_{n−k}−a_1,h_{n−k+1}−a_2,…,h_n−a_k$ for some $k$ fixed elements $a_1,a_2,…,a_k$ of the base ring. This generalizes both the classical and the quantum cohomology rings of $Gr(k,n)$. We find three bases for the new quotient, as well as an $S_3$-symmetry of its structure constants, a “rim hook rule” for straightening arbitrary Schur polynomials, and a fairly complicated Pieri rule. We conjecture that the structure constants are nonnegative in an appropriate sense (treating the $a_i$ as signed indeterminate), which suggests a geometric or combinatorial meaning for the quotient.

Information about the video

Domain(s)

Document(s)

Last related questions on MathOverflow

You have to connect your Carmin.tv account with mathoverflow to add question

Ask a question on MathOverflow




Register

  • Bookmark videos
  • Add videos to see later &
    keep your browsing history
  • Comment with the scientific
    community
  • Get notification updates
    for your favorite subjects
Give feedback