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We consider tangent cones of Schubert varieties in the complete flag variety, and investigate the problem when the tangent cones of two different Schubert varieties coincide. We give a sufficient condition for such coincidence, and…

Representation Theory · Mathematics 2017-06-12 Dmitry Fuchs , Alexandre Kirillov , Sophie Morier-Genoud , Valentin Ovsienko

Cominuscule flag varieties generalize Grassmannians to other Lie types. Schubert varieties in cominuscule flag varieties are indexed by posets of roots labeled long/short. These labeled posets generalize Young diagrams. We prove that…

Combinatorics · Mathematics 2024-03-26 Edward Richmond , Mihail Tarigradschi , Weihong Xu

We show that in type A or C any degenerate flag variety is in fact isomorphic to a Schubert variety in an appropriate partial flag manifold.

Representation Theory · Mathematics 2014-07-17 Giovanni Cerulli Irelli , Martina Lanini

We generalize the classification of isomorphism classes of Schubert varieties in complete flag varieties G/B to a class of partial flag varieties G/P. In particular, we classify all Schubert varieties in G/P where P is a minimal parabolic…

Combinatorics · Mathematics 2025-11-25 Yanjun Chen

A flag variety is a homogenous variety $G/B$ where $G$ is a simple algebraic group over the complex numbers and $B$ is a Boel subgroup of $G$. A Schubert variety $X_w$ is a subvariety of $G/B$ indexed by an element $w$ in the Weyl group of…

Algebraic Geometry · Mathematics 2023-11-21 Eunjeong Lee , Mikiya Masuda , Seonjeong Park

In this work we extend some previously known results on the automorphism group of Schubert varieties. We consider the Schubert conditions which define a Schubert variety. An automorphism of the Grassmannian fixes a Schubert variety…

Algebraic Geometry · Mathematics 2017-01-10 Fernando Piñero

Characteristic classes of Schubert varieties can be used to study the geometry and the combinatorics of homogeneous spaces. We prove a relation between elliptic classes of Schubert varieties on a generalized full flag variety and those on…

Algebraic Geometry · Mathematics 2021-01-01 Richard Rimanyi , Andrzej Weber

The Schubert varieties on a flag manifold G/P give rise to a cell decomposition on G/P whose Kronecker duals, known as the Schubert classes on G/P, form an additive base of the integral cohomology of G/P. The Schubert's problem of…

Algebraic Topology · Mathematics 2020-11-02 Haibao Duan , Xuezhi Zhao

We prove that Schubert varieties in potentially different Grassmannians are isomorphic as varieties if and only if their corresponding Young diagrams are identical up to a transposition. We also discuss a generalization of this result to…

Algebraic Geometry · Mathematics 2023-09-13 Mihail Tarigradschi , Weihong Xu

Let $P$ be a parabolic subgroup in $SL_n(\mathbb C)$. We show that there is a $SL_n(\mathbb C)$-stable closed subvariety of an affine Schubert variety in an infinite dimensional partial Flag variety (associated to the Kac-Moody group…

Algebraic Geometry · Mathematics 2017-05-10 Venkatramani Lakshmibai , Rahul Singh

After proving that every Schubert variety in the full flag variety of a complex reductive group $G$ is a general Hessenberg variety, we show that not all such Schubert varieties are adjoint Hessenberg varieties. In fact, in types A and C,…

Algebraic Geometry · Mathematics 2021-07-19 Laura Escobar , Martha Precup , John Shareshian

Schubert varieties in finite dimensional flag manifolds G/P are a well-studied family of projective varieties indexed by elements of the corresponding Weyl group W. In particular, there are many tests for smoothness and rational smoothness…

Combinatorics · Mathematics 2010-09-01 Sara Billey , Andrew Crites

We characterize complete intersection matrix Schubert varieties, generalizing the classical result on one-sided ladder determinantal varieties. We also give a new proof of the F-rationality of matrix Schubert varieties. Although it is known…

Algebraic Geometry · Mathematics 2013-10-25 Jen-Chieh Hsiao

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

We describe the action of the Weyl group of a semi simple linear group $G$ on cohomological and K-theoretic invariants of the generalized flag variety $G/B$. We study the automorphism $s_i$, induced by the reflection in the simple root, on…

Algebraic Geometry · Mathematics 2024-05-28 Mieszko Baszczak

Given a singular Schubert variety Z in a compact Hermitian symmetric space it is a longstanding question to determine when Z is homologous to a smooth variety Y. We identify those Schubert varieties for which there exist first-order…

Differential Geometry · Mathematics 2011-02-10 C. Robles , D. The

We extend the short presentation due to [Borel '53] of the cohomology ring of a generalized flag manifold to a relatively short presentation of the cohomology of any of its Schubert varieties. Our result is stated in a root-system uniform…

Combinatorics · Mathematics 2010-11-29 Victor Reiner , Alexander Woo , Alexander Yong

We show that there is a ${SL_n}$-stable closed subset of an affine Schubert variety in the infinite dimensional Flag variety (associated to the Kac-Moody group ${\widehat{SL_n}}$) which is a natural compactification of the cotangent bundle…

Algebraic Geometry · Mathematics 2022-03-29 V. Lakshmibai , C. S. Seshadri , R. Singh

We show that there is an affine Schubert variety in the infinite dimensional partial Flag variety (associated to the two- step parabolic subgroup of the Kac-Moody group {\hat SL(n)}, corresponding to omitting {\alpha}_0,{\alpha}_d) which is…

Algebraic Geometry · Mathematics 2015-05-04 V. Lakshmibai

Our concern in this paper is the dimension and inclusion relations of Schubert varieties in twisted partial affine flag varieties. In the end we apply our results to some local models of certain Schubert varieties.

Algebraic Geometry · Mathematics 2010-11-25 Timo Richarz
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