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Related papers: Schubert duality for SL(n,R)-flag domains

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Let X be the flag variety of the symplectic group. We propose a theory of combinatorially explicit Schubert polynomials which represent the Schubert classes in the Borel presentation of the cohomology ring of X. We use these polynomials to…

Algebraic Geometry · Mathematics 2014-02-26 Harry Tamvakis

The self-duality of the paracyclic category is extended to a certain class of homotopy categories of (2,1)-categories. These generalise the orbit category of a group and are associated to certain self-dual preorders equipped with a presheaf…

Category Theory · Mathematics 2022-02-28 John Boiquaye , Philipp Joram , Ulrich Krähmer

We describe the loci of non-rationally smooth (nrs) points and of singular points for any non-spiral Schubert variety of $\tilde{A}_2$ in terms of the geometry of the (affine) Weyl group action on the plane $\mathbb{R}^2$. Together with the…

Algebraic Geometry · Mathematics 2024-07-31 Brian D. Boe , William Graham

We provide a proof that every Schubert variety of a semi-infinite flag variety is projectively normal. This gives us an interpretation of a Demazure module of a global Weyl module of a current Lie algebra as the (dual) space of the space of…

Representation Theory · Mathematics 2018-09-06 Syu Kato

We consider tangent cones to Schubert subvarieties of the flag variety $G/B$, where $B$ is a Borel subgroup of a reductive complex algebraic group $G$ of type $E_6$, $E_7$ or $E_8$. We prove that if $w_1$ and $w_2$ form a good pair of…

Algebraic Geometry · Mathematics 2020-07-09 Mikhail V. Ignatyev , Aleksandr A. Shevchenko

We study a family of polynomials whose values express degrees of Schubert varieties in the generalized complex flag manifold G/B. The polynomials are given by weighted sums over saturated chains in the Bruhat order. We derive several…

Combinatorics · Mathematics 2007-05-23 Alexander Postnikov , Richard P. Stanley

Points in the intersection of Schubert varieties are counted by various combinatorial objects, for example standard tableaux. This paper consider the problem of producing a natural labelling of intersection points by these combinatorial…

Representation Theory · Mathematics 2019-12-24 Noah White

Let G be a connected, reductive algebraic group over an algebraically closed field of characteristic zero or good and odd. We characterize the spherical conjugacy classes of G as those intersecting only Bruhat cells corresponding to…

Group Theory · Mathematics 2009-02-05 Giovanna Carnovale

We show that canonical bases in $\dot{U}(\mathfrak{sl}_n)$ and the Schur algebra are compatible; in fact we extend this result to $p$-canonical bases. This follows immediately from a fullness result from a functor categorifying this map. In…

Representation Theory · Mathematics 2017-11-15 Ben Webster

We introduce a stratification on the space of symplectic flags on the de Rham bundle of the universal principally polarized abelian variety in positive characteristic and study its geometric properties like irreducibility of the strata and…

Algebraic Geometry · Mathematics 2007-05-23 Torsten Ekedahl , Gerard van der Geer

In this paper we study domains in flag manifolds which are bounded in an affine chart and whose projective automorphism group acts co-compactly. In contrast to the many examples in real projective space, we will show that no examples exist…

Differential Geometry · Mathematics 2018-01-26 Andrew Zimmer

We study the geometry of equicharacteristic partial affine flag varieties associated to tamely ramified groups $G$ in characteristics $p>0$ dividing the order of the fundamental group $\pi_1(G_{\text{der}})$. We obtain that most Schubert…

Algebraic Geometry · Mathematics 2022-10-06 Thomas J. Haines , João Lourenço , Timo Richarz

Let $G$ be a compact and $1$--connected Lie group with a maximal torus $T$. Based on Schubert calculus on the flag manifold $G/T$ [15] we construct the integral cohomology ring $H^{\ast}(G)$ uniformly for all $G$.

Algebraic Topology · Mathematics 2015-09-11 Haibao Duan , Xuezhi Zhao

We study certain real Lie-group orbits in the compact duals of Mumford-Tate domains, verifying a prediction made in [Green, Griffiths, Kerr; Mumford-Tate domains: their geometry and arithmetic] and determining which orbits contain a limit…

Algebraic Geometry · Mathematics 2013-07-31 Matt Kerr , Gregory Pearlstein

We consider the action of the Levi subgroup of a parabolic subgroup that stabilizes a Schubert variety. We show that a smooth Schubert variety is a homogeneous space for a parabolic subgroup, or it has a smooth Schubert divisor. Further, we…

Algebraic Geometry · Mathematics 2020-03-06 Mahir Bilen Can , Reuven Hodges

We prove that the prime torsion in the local integral intersection cohomology of Schubert varieties in the flag variety of the general linear group grows exponentially in the rank. The idea of the proof is to find a highly singular point in…

Algebraic Geometry · Mathematics 2015-12-29 Geordie Williamson

In this paper, as in our previous "Descent-cycling in Schubert calculus" math.CO/0009112, we study the structure constants in equivariant cohomology of flag manifolds G/B. In this one we give a recurrence (which is frequently, but alas not…

Combinatorics · Mathematics 2007-05-23 Allen Knutson

In this paper, a description of the set-theoretical defining equations of symplectic (type C) Grassmannian/flag/Schubert varieties in corresponding (type A) algebraic varieties is given as linear polynomials in Pl$\ddot{u}$cker coordinates,…

Algebraic Geometry · Mathematics 2023-04-21 Jiajun Xu , Guanglian Zhang

A flag manifold over a semifield K can be partitioned into "half i-circles" which are orbits of a K-action on that flag manifold. Here i is fixed and it corresponds to a simple reflection in the Weyl group. We prove (for certain K) a…

Representation Theory · Mathematics 2022-12-21 G. Lusztig

We compute the Hochschild, cyclic, and periodic cyclic homology groups of algebras of families of Laurent complete symbols on manifolds with corners. We show in particular that the spectral sequence associated with Hochschild homology…

K-Theory and Homology · Mathematics 2007-05-23 Moulay Benameur , Victor Nistor
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