RSK-Complete Cycle Decompositions

CSEF · 2023 Mathematical Sciences Second Award

Overview

The Robinson-Schensted-Knuth (RSK) Correspondence is a mathematical mapping that takes a permutation and uniquely maps it to a pair of Young tableaux. This correspondence has been the subject of much study since it behaves well under operations like inversion and reversal, and the shapes of the resulting tableaux directly describe increasing subsequences within the permutation. This project aims to deepen our understanding of the RSK correspondence by examining the connection between the graphical representation of a permutation and the shapes of its corresponding Young tableaux. It is well known that every shape can be generated by exactly one involution (permutations with cycles of length at most two). We complement this classical result by examining the connection between permutations with large cycles and their resultant shapes. Last year, we showed that cyclic permutations can generate all RSK shapes (other than the two trivial shapes consisting of a single row or column) for a given n, a property that we call RSK-completeness. While this was a good first step, it offered no insight into the RSK-completeness of any other cycle decomposition. This year, we fully characterize the property of RSK-completeness across all cycle decompositions. This involves two significant new results. On the constructive side, we show that almost cyclic permutations (with one element mapping to itself and the rest of the permutation forming a cycle) are RSK-compete for odd n. And most interestingly, we show that no other cycle decomposition can be RSK-complete, completing our investigation of this important problem.

Source coverage

This record comes from a published award list, not a complete project archive. Its abstract comes from CSEF's public project showcase as archived by the Internet Archive before judging (https://web.archive.org/web/20230401224130/https://ca-csef.zfairs.com/showcase/ShowcaseInfo?f=838e60b7-ea75-46e8-865c-fde4864244b3); the version presented may differ.

Awards (1)

Competition history

  • CSEF 2023 Mathematical Sciences · Entry S1402

Resources

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