A skew Specht perspective of RoCK blocks and cuspidal systems for KLR algebras in affine type A

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Hauptverfasser: Muth, Robert, Nicewicz, Thomas, Speyer, Liron, Sutton, Louise
Format: Preprint
Veröffentlicht: 2024
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author Muth, Robert
Nicewicz, Thomas
Speyer, Liron
Sutton, Louise
author_facet Muth, Robert
Nicewicz, Thomas
Speyer, Liron
Sutton, Louise
contents Cuspidal systems parameterize KLR algebra representations via root partitions $π$, where simple modules $L(π)$ arise as heads of proper standard modules. Working in affine type A with an arbitrary convex preorder, we construct explicit skew diagrams $ζ(π)$ such that the skew Specht module $S^{ζ(π)}$ has simple head $L(π)$ and a filtration by proper standard modules. A key ingredient in this construction is the development of `core-truncation' functors, which take module categories of level one RoCK blocks to the category of imaginary semicuspidal KLR modules. Every simple imaginary semicuspidal module arises in the image of these functors. This result stems from an in-depth study of the combinatorial interplay between cuspidal systems and RoCK cyclotomic KLR algebras, in which we characterize core blocks and RoCK blocks in arbitrary level via cuspidal tiling properties of multipartitions in these blocks.
format Preprint
id arxiv_https___arxiv_org_abs_2405_15759
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A skew Specht perspective of RoCK blocks and cuspidal systems for KLR algebras in affine type A
Muth, Robert
Nicewicz, Thomas
Speyer, Liron
Sutton, Louise
Representation Theory
Combinatorics
20C08, 20C30, 05E10, 05E16, 17B22
Cuspidal systems parameterize KLR algebra representations via root partitions $π$, where simple modules $L(π)$ arise as heads of proper standard modules. Working in affine type A with an arbitrary convex preorder, we construct explicit skew diagrams $ζ(π)$ such that the skew Specht module $S^{ζ(π)}$ has simple head $L(π)$ and a filtration by proper standard modules. A key ingredient in this construction is the development of `core-truncation' functors, which take module categories of level one RoCK blocks to the category of imaginary semicuspidal KLR modules. Every simple imaginary semicuspidal module arises in the image of these functors. This result stems from an in-depth study of the combinatorial interplay between cuspidal systems and RoCK cyclotomic KLR algebras, in which we characterize core blocks and RoCK blocks in arbitrary level via cuspidal tiling properties of multipartitions in these blocks.
title A skew Specht perspective of RoCK blocks and cuspidal systems for KLR algebras in affine type A
topic Representation Theory
Combinatorics
20C08, 20C30, 05E10, 05E16, 17B22
url https://arxiv.org/abs/2405.15759