Simple Procedures for Left and Right Keys of Semi-Standard Young Tableaux

Fuente: arXiv
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Autori principali: Kushwaha, Mrigendra Singh, Raghavan, K. N., Viswanath, Sankaran
Natura: Preprint
Pubblicazione: 2023
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author Kushwaha, Mrigendra Singh
Raghavan, K. N.
Viswanath, Sankaran
author_facet Kushwaha, Mrigendra Singh
Raghavan, K. N.
Viswanath, Sankaran
contents We give simple procedures to obtain the left and right keys of a semi-standard Young tableau. Keys derive their interest from the fact that they encode the characters of Demazure and opposite Demazure modules for the general and special linear groups. Given the importance of keys, there are indeed several procedures available in the literature to determine them. In comparison, our procedures are new (to the best of our knowledge) and especially simple. Having said that, we hasten to add that there is nothing new in any individual ingredient that goes into our procedures. These ingredients are all routine, straightforward, and (in any case) occur in the literature. But they never quite seem to have been put together as done here. Our procedures end up repeatedly performing the Deodhar lifts, maximal lifts for the left key and minimal lifts for right key. Together with the well known fact that keys can be obtained by such repeated lifts, this justifies the procedures. The relevance of Deodhar lifts to combinatorial models for Demazure characters is well known in Standard Monomial Theory. Right and left keys appear respectively as initial and final directions of Lakshmibai-Seshadri paths in Littelmanns Path Model Theory.
format Preprint
id arxiv_https___arxiv_org_abs_2302_08279
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Simple Procedures for Left and Right Keys of Semi-Standard Young Tableaux
Kushwaha, Mrigendra Singh
Raghavan, K. N.
Viswanath, Sankaran
Combinatorics
05E10, 17B10, 22E46
We give simple procedures to obtain the left and right keys of a semi-standard Young tableau. Keys derive their interest from the fact that they encode the characters of Demazure and opposite Demazure modules for the general and special linear groups. Given the importance of keys, there are indeed several procedures available in the literature to determine them. In comparison, our procedures are new (to the best of our knowledge) and especially simple. Having said that, we hasten to add that there is nothing new in any individual ingredient that goes into our procedures. These ingredients are all routine, straightforward, and (in any case) occur in the literature. But they never quite seem to have been put together as done here. Our procedures end up repeatedly performing the Deodhar lifts, maximal lifts for the left key and minimal lifts for right key. Together with the well known fact that keys can be obtained by such repeated lifts, this justifies the procedures. The relevance of Deodhar lifts to combinatorial models for Demazure characters is well known in Standard Monomial Theory. Right and left keys appear respectively as initial and final directions of Lakshmibai-Seshadri paths in Littelmanns Path Model Theory.
title Simple Procedures for Left and Right Keys of Semi-Standard Young Tableaux
topic Combinatorics
05E10, 17B10, 22E46
url https://arxiv.org/abs/2302.08279