2025/06/13 by Lee, Mitchell
#05E05 #Combinatorics (math.CO) #FOS: Mathematics #Representation Theory (math.RT)
paper · doi:10.48550/arxiv.2506.11837
Let r ≥ 0, and let λ and μ be partitions such that λ1 ≤ r + 1. We present a combinatorial interpretation of the plethysm coefficient ⟨ sλ, sμ[sr] ⟩. As a consequence, we solve the restriction problem for partitions with at most three columns. That is, for all partitions λ with λ1 ≤ 3, we find a combinatorial interpretation for the multiplicities of the irreducible \mathfrakSn-submodules of the Schur module \mathbbSλℂn, considered as an \mathfrakSn-module.