Schubert variety
In algebraic geometry, a Schubert variety is a certain subvariety of a Grassmannian, G r k ( V ) {\displaystyle \mathbf {Gr} _{k}(V)} of k {\displaystyle k} -dimensional subspaces of a vector space V {\displaystyle V} , usually with singular points. Like the Grassmannian, it is a kind of moduli space, whose elements satisfy conditions giving lower bounds to the dimensions of the intersections of its elements w ⊂ V {\displaystyle w\subset V} , with the elements of a specified complete flag.