English

Comparing $GL_n$-Representations by Characteristic-Free Isomorphisms between Generalized Schur Algebras

Representation Theory 2007-08-31 v1

Abstract

Isomorphisms are constructed between generalized Schur algebras in different degrees. The construction covers both the classical case (of general linear groups over infinite fields of arbitrary characteristic) and the quantized case (in type AA, for any non-zero value of the quantum parameter qq). The construction does not depend on the characteristic of the underlying field or the choice of q0q \neq 0. The proof combines a combinatorial construction with comodule structures and Ringel duality. Applications range from equivalences of categories to results on the structure and cohomology of Schur algebras to identities of decomposition numbers and also of pp-Kostka numbers, in both cases reproving and generalizing row and column removal rules.

Keywords

Cite

@article{arxiv.0708.4019,
  title  = {Comparing $GL_n$-Representations by Characteristic-Free Isomorphisms between Generalized Schur Algebras},
  author = {Ming Fang and Anne Henke and Steffen Koenig},
  journal= {arXiv preprint arXiv:0708.4019},
  year   = {2007}
}
R2 v1 2026-06-21T09:12:02.513Z