English

Tilting modules, dominant dimensions and Brauer-Schur-Weyl duality

Representation Theory 2021-06-15 v2

Abstract

Let AA be a standardly stratified algebra over a field KK and TT a tilting module over AA. Let Λ+\Lambda^+ be an indexing set of all simple modules in A\lmodA\lmod. We show that if there is an integer rNr\in\N such that for any λΛ+\lambda\in\Lambda^+, there is an embedding Δ(λ)Tr\Delta(\lambda)\hookrightarrow T^{\oplus r} as well as an epimorphism Tr(λ)T^{\oplus r}\twoheadrightarrow\overline{\nabla}(\lambda) as AA-modules, then TT is a faithful AA-module and AA has the double centraliser property with respect to TT. As applications, we prove that if AA is quasi-hereditary with a simple preserving duality and TT a given faithful tilting AA-module, then AA has the double centralizer property with respect to TT. This provides a simple and useful criterion which can be applied in many situations in algebraic Lie theory. We affirmatively answer a question of Mazorchuk and Stroppel by proving the existence of a unique minimal basic tilting module TT over AA for which A=\End\EndA(T)(T)A=\End_{\End_A(T)}(T). We also establish a Schur-Weyl duality between the symplectic Schur algebra Ssy(m,n)S^{sy}(m,n) and \bbn/Bn(f)\bb_{n}/\mathfrak{B}_{n}^{(f)} on Vn/VnBn(f)V^{\otimes n}/V^{\otimes n}\mathfrak{B}_{n}^{(f)} when \chaK>min{nf+m,n}\cha K>\min\{n-f+m,n\}, where VV is a 2m2m-dimensional symplectic space over KK, Bn(f)\mathfrak{B}_{n}^{(f)} is the two-sided ideal of the Brauer algebra \bbn(2m)\bb_{n}(-2m) generated by e1e3e2f1e_1e_3\cdots e_{2f-1} with 1f[n2]1\leq f\leq [\frac{n}{2}].

Keywords

Cite

@article{arxiv.2005.02306,
  title  = {Tilting modules, dominant dimensions and Brauer-Schur-Weyl duality},
  author = {Jun Hu and Zhankui Xiao},
  journal= {arXiv preprint arXiv:2005.02306},
  year   = {2021}
}

Comments

18 pages

R2 v1 2026-06-23T15:19:43.636Z