Affine flag varieties and quantum symmetric pairs

Fuente: arXiv
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Autores principales: Fan, Zhaobing, Lai, Chun-Ju, Li, Yiqiang, Luo, Li, Wang, Weiqiang
Formato: Preprint
Publicado: 2016
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author Fan, Zhaobing
Lai, Chun-Ju
Li, Yiqiang
Luo, Li
Wang, Weiqiang
author_facet Fan, Zhaobing
Lai, Chun-Ju
Li, Yiqiang
Luo, Li
Wang, Weiqiang
contents The quantum groups of finite and affine type $A$ admit geometric realizations in terms of partial flag varieties of finite and affine type $A$. Recently, the quantum group associated to partial flag varieties of finite type $B/C$ is shown to be a coideal subalgebra of the quantum group of finite type $A$. In this paper we study the structures of Schur algebras and Lusztig algebras associated to (four variants of) partial flag varieties of affine type $C$. We show that the quantum groups arising from Lusztig algebras and Schur algebras via stabilization procedures are (idempotented) coideal subalgebras of quantum groups of affine $\mathfrak{sl}$ and $\mathfrak{gl}$ types, respectively. In this way, we provide geometric realizations of eight quantum symmetric pairs of affine types. We construct monomial and canonical bases of all these quantum (Schur, Lusztig, and coideal) algebras. For the idempotented coideal algebras of affine $\mathfrak{sl}$ type, we establish the positivity properties of the canonical basis with respect to multiplication, comultiplication and a bilinear pairing. In particular, we obtain a new and geometric construction of the idempotented quantum affine $\mathfrak{gl}$ and its canonical basis.
format Preprint
id arxiv_https___arxiv_org_abs_1602_04383
institution arXiv
publishDate 2016
record_format arxiv
spellingShingle Affine flag varieties and quantum symmetric pairs
Fan, Zhaobing
Lai, Chun-Ju
Li, Yiqiang
Luo, Li
Wang, Weiqiang
Representation Theory
Algebraic Geometry
Quantum Algebra
17B37, 20G25, 14F43
The quantum groups of finite and affine type $A$ admit geometric realizations in terms of partial flag varieties of finite and affine type $A$. Recently, the quantum group associated to partial flag varieties of finite type $B/C$ is shown to be a coideal subalgebra of the quantum group of finite type $A$. In this paper we study the structures of Schur algebras and Lusztig algebras associated to (four variants of) partial flag varieties of affine type $C$. We show that the quantum groups arising from Lusztig algebras and Schur algebras via stabilization procedures are (idempotented) coideal subalgebras of quantum groups of affine $\mathfrak{sl}$ and $\mathfrak{gl}$ types, respectively. In this way, we provide geometric realizations of eight quantum symmetric pairs of affine types. We construct monomial and canonical bases of all these quantum (Schur, Lusztig, and coideal) algebras. For the idempotented coideal algebras of affine $\mathfrak{sl}$ type, we establish the positivity properties of the canonical basis with respect to multiplication, comultiplication and a bilinear pairing. In particular, we obtain a new and geometric construction of the idempotented quantum affine $\mathfrak{gl}$ and its canonical basis.
title Affine flag varieties and quantum symmetric pairs
topic Representation Theory
Algebraic Geometry
Quantum Algebra
17B37, 20G25, 14F43
url https://arxiv.org/abs/1602.04383