English

Contravariant forms and extremal projectors

Quantum Algebra 2019-11-26 v2

Abstract

Tensor product of irreducible modules of highest weight over a semi-simple quantum group is semi-simple if and only if a natural contravariant form is non-degenerate when restricted to the span of singular vectors. We express this restriction through the extremal projector of the quantum group providing a computationally feasible criterion for complete reducibility of tensor products.

Keywords

Cite

@article{arxiv.1911.09933,
  title  = {Contravariant forms and extremal projectors},
  author = {Andrey Mudrov},
  journal= {arXiv preprint arXiv:1911.09933},
  year   = {2019}
}

Comments

21 pages, a typo corrected

R2 v1 2026-06-23T12:24:19.299Z