Séminaire Lotharingien de Combinatoire, 93B.96 (2025), 12 pp.

Robert Muth, Thomas Nicewicz, Liron Speyer and Louise Sutton

Simple Modules for Affine Type A KLR/I> Algebras via Skew Specht Modules

Abstract. Cuspidal systems parameterise KLR algebra representations via root partitions π, where simple modules L(π) arise as heads of proper standard modules. We define a combinatorial dilation map and construct skew Young diagrams ζ(π) associated to each root partition π in an arbitrary convex order in affine type A. These skew diagrams have the property that the corresponding skew Specht module Sζ(π) has simple head L(π) and a filtration by proper standard modules. Our results represent a far more explicit and combinatorial construction of these modules than was previously known.


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

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