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Related papers: Restricting Schubert classes

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Let X be an orthogonal Grassmannian parametrizing isotropic subspaces in an even dimensional vector space equipped with a nondegenerate symmetric form. We prove a Giambelli formula which expresses an arbitrary Schubert class in the singular…

Algebraic Geometry · Mathematics 2012-04-02 Anders S. Buch , Andrew Kresch , Harry Tamvakis

We give a closed-form formula for the Hilbert function of the tangent cone at the identity of a Schubert variety X in the Grassmannian in both group theoretic and combinatorial terms. We also give a formula for the multiplicity of X at the…

Algebraic Geometry · Mathematics 2007-05-23 V. Kreiman , V. Lakshmibai

Given a simply-connected simple algebraic group $G$, we determine the tangent space of any Finkelberg-Mirkovi\'c Schubert scheme at the base point of the affine Grassmannian of $G$. As a consequence, we exhibit non-reduced…

Representation Theory · Mathematics 2026-04-14 Marc Besson , Jiuzu Hong , Huanhuan Yu

Let $\mathbb{G}(d,n)$ be the complex Grassmannian of affine $d$-planes in $n$-space. We study the problem of characterizing the set of algebraic subvarieties of $\mathbb{G}(d,n)$ invariant under the action of the maximal torus $T$ and…

Algebraic Geometry · Mathematics 2025-03-10 E. Javier Elizondo , Alex Fink , Cristhian Garay López

Here we give brief account of hermitian symplectic spaces, showing that they are intimately connected to symmetric as well as self-adjoint extensions of a symmetric operator. Furthermore we find an explicit parameterisation of the Lagrange…

Mathematical Physics · Physics 2007-05-23 M. Harmer

It is shown that any bounded metric space can be isometrically embedded into the Gromov--Hausdorff metric class GH. This result is a consequence of local geometry description of the class GH in a sufficiently small neighborhood of a generic…

Metric Geometry · Mathematics 2022-03-08 Alexander O. Ivanov , Alexey A. Tuzhilin

Let G be the group preserving a nondegenerate sesquilinear form on a vector space V, and H a symmetric subgroup of G of the type G1 x G2. We explicitly parameterize the H-orbits in the Grassmannian of r-dimensional isotropic subspaces of V…

Representation Theory · Mathematics 2011-04-27 Huajun Huang , Hongyu He

This work concerns the relation between the geometry of Lagrangian Grassmannians and the CKP integrable hierarchy. The Lagrange map from the Lagrangian Grassmannian of maximal isotropic (Lagrangian) subspaces of a finite dimensional…

Mathematical Physics · Physics 2023-08-02 S. Arthamonov , J. Harnad , J. Hurtubise

In this paper, we propose a construction of GLSM defects corresponding to Schubert cycles in Lagrangian Grassmannians, following recent work of Closset-Khlaif on Schubert cycles in ordinary Grassmannians. In the case of Lagrangian…

High Energy Physics - Theory · Physics 2025-06-17 W. Gu , L. Mihalcea , E. Sharpe , W. Xu , H. Zhang , H. Zou

Let G be any of the complex classical groups GL(n), SO(2n+1), Sp(2n), O(2n), let g denote the Lie algebra of G, and let Z(g) denote the subalgebra of G-invariants in the universal enveloping algebra U(g). We derive a Taylor-type expansion…

q-alg · Mathematics 2008-03-02 Andrei Okounkov , Grigori Olshanski

We study the arc space of the Grassmannian from the point of view of the singularities of Schubert varieties. Our main tool is a decomposition of the arc space of the Grassmannian that resembles the Schubert cell decomposition of the…

Algebraic Geometry · Mathematics 2016-12-15 Roi Docampo , Antonio Nigro

Let $G/P$ be a generalized flag variety, where $G$ is a complex semisimple connected Lie group and $P\subset G$ a parabolic subgroup. Let also $X\subset G/P$ be a Schubert variety. We consider the canonical embedding of $X$ into a…

Symplectic Geometry · Mathematics 2009-05-28 Augustin-Liviu Mare

Consider k x n matrices with rank conditions placed on intervals of columns. The ranks that are actually achievable correspond naturally to upper triangular partial permutation matrices, and we call the corresponding subvarieties of Gr(k,n)…

Algebraic Geometry · Mathematics 2014-08-07 Allen Knutson

Given a finite-dimensional inner product space $V$ and a group $G$ of isometries, we consider the problem of embedding the orbit space $V/G$ into a Hilbert space in a way that preserves the quotient metric as well as possible. This inquiry…

Metric Geometry · Mathematics 2025-06-06 Ben Blum-Smith , Harm Derksen , Dustin G. Mixon , Yousef Qaddura , Brantley Vose

In a classical-type flag variety, we consider a Schubert variety associated to a vexillary (signed) permutation, and establish a combinatorial formula for the Hilbert-Samuel multiplicity of a point on such a Schubert variety. The formula is…

Algebraic Geometry · Mathematics 2021-12-15 David Anderson , Takeshi Ikeda , Minyoung Jeon , Ryotaro Kawago

We express a Schubert expansion of the Chern-Mather class for Schubert varieties in the even orthogonal Grassmannian via integrals involving Pfaffians and pushforward of the small resolutions in the sense of Intersection Cohomology (IH)…

Algebraic Geometry · Mathematics 2023-03-31 Minyoung Jeon

Brasselet, the second author and Yokura introduced Hodge-theoretic Hirzebruch-type characteristic classes $IT_{1, \ast}$, and conjectured that they are equal to the Goresky-MacPherson $L$-classes for pure-dimensional compact complex…

Algebraic Geometry · Mathematics 2023-10-24 Markus Banagl , Jörg Schürmann , Dominik J. Wrazidlo

The Grassmannian model represents harmonic maps from Riemann surfaces by families of shift-invariant subspaces of a Hilbert space. We impose a natural symmetry condition on the shift-invariant subspaces that corresponds to considering an…

Functional Analysis · Mathematics 2019-12-06 Alexandru Aleman , Rui Pacheco , John C. Wood

In this note, we discuss the flexibility of Schubert classes in homogeneous varieties. We give several constructions for representing multiples of a Schubert class by irreducible subvarieties. We sharpen [R, Theorem 3.1] by proving that…

Algebraic Geometry · Mathematics 2013-03-04 Izzet Coskun , Colleen Robles

For an arbitrary field of any characteristic we give an explicit description, in terms of Pl\"ucker coordinates, of the projective linear space that cuts out the Lagrangian-Grassmannian variety $L(n,2n)$ of maximal isotropic subspaces in a…

Symplectic Geometry · Mathematics 2016-01-28 J. Carrillo-Pacheco , F. Jarquín-Zárate , M. Velasco-Fuentes , F. Zaldívar