The projective cover of tableau-cyclic indecomposable $H_n(0)$-modules
Abstract
Let be a composition of and a permutation in . This paper concerns the projective covers of -modules , and , which categorify the dual immaculate quasisymmetric function, the extended Schur function, and the quasisymmetric Schur function when is the identity, respectively. First, we show that the projective cover of is the projective indecomposable module due to Norton, and and the -twist of the canonical submodule of for 's satisfying suitable conditions appear as -homomorphic images of . Second, we introduce a combinatorial model for the -twist of and derive a series of surjections starting from to the -twist of . Finally, we construct the projective cover of every indecomposable direct summand of . As a byproduct, we give a characterization of triples such that the projective cover of is indecomposable.
Keywords
Cite
@article{arxiv.2008.06830,
title = {The projective cover of tableau-cyclic indecomposable $H_n(0)$-modules},
author = {Seung-Il Choi and Young-Hun Kim and Sun-Young Nam and Young-Tak Oh},
journal= {arXiv preprint arXiv:2008.06830},
year = {2022}
}
Comments
40 pages, Online published in TAMS