English

Projective normality of torus quotients of flag varieties

Representation Theory 2019-09-18 v2

Abstract

Let G=SLn(C)G=SL_n(\mathbb C) and TT be a maximal torus in GG. We show that the quotient T\\G/Pα1Pα2T \backslash \backslash G/{P_{\alpha_1}\cap P_{\alpha_2}} is projectively normal with respect to the descent of a suitable line bundle, where PαiP_{\alpha_i} is the maximal parabolic subgroup in GG associated to the simple root αi\alpha_i, i=1,2i=1,2. We give a degree bound of the generators of the homogeneous coordinate ring of T\\(G3,6)Tss(L2ϖ3)T \backslash \backslash (G_{3,6})^{ss}_T(\mathcal{L}_{2\varpi_3}). If G=Spin7G =Spin_7, we give a degree bound of the generators of the homogeneous coordinate ring of T\\(G/Pα2)Tss(L2ϖ2)T \backslash \backslash (G/P_{\alpha_2})^{ss}_T(\mathcal{L}_{2\varpi_2}) whereas we prove that the quotient T\\(G/Pα3)Tss(L4ϖ3)T\backslash\backslash (G/P_{\alpha_3})^{ss}_T(\mathcal{L}_{4\varpi_3}) is projectively normal with respect to the descent of the line bundles L4ϖ3\mathcal{L}_{4\varpi_3}.

Keywords

Cite

@article{arxiv.1906.09759,
  title  = {Projective normality of torus quotients of flag varieties},
  author = {Arpita Nayek and Santosha Kumar Pattanayak and Shivang Jindal},
  journal= {arXiv preprint arXiv:1906.09759},
  year   = {2019}
}