# Introduction to Back-Stable Schubert Polynomials

I’ll define double back-stable Schubert polynomials (in the form Dave Anderson and I gave a couple of years ago). I’ll show that they are characterized by the way that they count points in loci defined by rank conditions on matrices. I’ll state some of their main properties. And I’ll describe how they relate to the bumpless pipe-dream formula of Lam-Lee-Shimozono.

**Date published:**Wednesday, March 29, 2023