Positroids and Schubert matroids
Combinatorics
2010-10-12 v5
Abstract
Postnikov gave a combinatorial description of the cells in a totally-nonnegative Grassmannian. These cells correspond to a special class of matroids called positroid. We prove his conjecture that a positroid is exactly an intersection of permuted Schubert matroids. This leads to a nice combinatorial description of positroids that is easily computable.
Cite
@article{arxiv.0803.1018,
title = {Positroids and Schubert matroids},
author = {Suho Oh},
journal= {arXiv preprint arXiv:0803.1018},
year = {2010}
}
Comments
10 pages, 1 figure. v5 simpler proof with improved writing. Submitted