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In algebraic geometry, the Bott–Samelson resolution of a Schubert variety is a resolution of singularities. It was introduced by in the context of compact Lie groups. The algebraic formulation is due to and . == Definition == Let ''G'' be a connected reductive complex algebraic group, ''B'' a Borel subgroup and ''T'' a maximal torus contained in ''B''. Let Any such ''w'' can be written as a product of reflections by simple roots. Fix minimal such an expression: : so that . (''l'' is the length of ''w''.) Let be the subgroup generated by ''B'' and a representative of . Let with respect to the action of by :. It is a smooth projective variety. Writing for the Schubert variety for ''w'', the multiplication map : and In other words, has rational singularities. There are also some other constructions; see, for example, . See also Bott–Samelson variety. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Bott–Samelson resolution」の詳細全文を読む スポンサード リンク
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