Séminaire Lotharingien de Combinatoire, 93B.4 (2025), 12 pp.

Álvaro Gutiérrez

Towards Plethystic sl2 Crystals

Abstract. To find crystals of sl2 representations of the form ΛnSymrC2 it suffices to solve the combinatorial problem of decomposing Young's lattice into rank-symmetric chains. We review the literature on this latter problem, and present a strategy to solve it. For n ≤ 4, the strategy recovers recently discovered solutions. We obtain (i) counting formulas for plethystic coefficients, (ii) new recursive formulas for plethysms of Schur functions, and (iii) formulas for the number of constituents of ΛnSymrC2.


Received: November 15, 2024. Accepted: February 15, 2025. Final version: April 1, 2025.

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