2022 report

RSK tableaux and the weak order on fully commutative permutations

(ArXiv Preprint No. 2212.05002).

By: E. Gunawan, J. Pan*, H. Russell & B. Tenner

UN Sustainable Development Goal Categories
11. Sustainable Cities and Communities (OpenAlex)
Source: NC State University Libraries
Added: March 31, 2023

For each fully commutative permutation, we construct a "boolean core," which is the maximal boolean permutation in its principal order ideal under the right weak order. We partition the set of fully commutative permutations into the recently defined crowded and uncrowded elements, distinguished by whether or not their RSK insertion tableaux satisfy a sparsity condition. We show that a fully commutative element is uncrowded exactly when it shares the RSK insertion tableau with its boolean core. We present the dynamics of the right weak order on fully commutative permutations, with particular interest in when they change from uncrowded to crowded. In particular, we use consecutive permutation patterns and descents to characterize the minimal crowded elements under the right weak order.