Positroids and Schubert matroids

JOURNAL OF COMBINATORIAL THEORY SERIES A

卷:118

Article

Oh, Suho

关键词: Positroid;    Matroid;    Schubert matroid;    Le-diagram;    Decorated permutation;    Totally nonnegative part of the Grassmannian;   

DOI  :  10.1016/j.jcta.2011.06.006

来源: Elsevier

【 摘 要 】

Postnikov gave a combinatorial description of the cells in a totally nonnegative Grassmannian. These cells correspond to a special class of matroids called positroids. We prove his conjecture that a positroid is exactly an intersection of cyclically shifted Schubert matroids. This leads to a combinatorial description of positroids that is easily computable. (C) 2011 Elsevier Inc. All rights reserved.

【 授权许可】

Free