English

Algebraic and geometric properties of flag Bott-Samelson varieties and applications to representations

Algebraic Geometry 2021-05-11 v3 Representation Theory

Abstract

We introduce the notion of flag Bott-Samelson variety as a generalization of Bott-Samelson variety and flag variety. Using a birational morphism from an appropriate Bott-Samelson variety to a flag Bott-Samelson variety, we compute Newton-Okounkov bodies of flag Bott-Samelson varieties as generalized string polytopes, which are applied to give polyhedral expressions for irreducible decompositions of tensor products of GG-modules. Furthermore, we show that flag Bott-Samelson varieties are degenerated into flag Bott manifolds with higher rank torus actions, and find the Duistermaat-Heckman measures of the moment map images of flag Bott-Samelson varieties with the torus action together with invariant closed 22-forms.

Keywords

Cite

@article{arxiv.1805.01664,
  title  = {Algebraic and geometric properties of flag Bott-Samelson varieties and applications to representations},
  author = {Naoki Fujita and Eunjeong Lee and Dong Youp Suh},
  journal= {arXiv preprint arXiv:1805.01664},
  year   = {2021}
}