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Schubert varieties have been exhaustively studied with a plethora of techniques: Coxeter groups, explicit desingularization, Frobenius splitting, etc. Many authors have applied these techniques to various other varieties, usually defined by…

Algebraic Geometry · Mathematics 2007-05-23 Peter Magyar

Let X be a smooth complex irreducible projective variety of dimension $n \geq 2$ and $H$ be an ample line bundle on $X$. In this paper, we construct families of $\mu_H$-stable vector bundles on $X$ having fixed determinant and rank $r$,…

Algebraic Geometry · Mathematics 2026-02-19 Sonia Brivio , Federico Fallucca , Filippo F. Favale

In this paper, we study the algebraic symplectic geometry of the singular moduli spaces of Higgs bundles of degree $0$ and rank $n$ on a compact Riemann surface $X$ of genus $g$. In particular, we prove that such moduli spaces are…

Algebraic Geometry · Mathematics 2017-01-27 Andrea Tirelli

We show that homologically projectively dual varieties for Grassmannians Gr(2,6) and Gr(2,7) are given by certain noncommutative resolutions of singularities of the corresponding Pfaffian varieties. As an application we describe the derived…

Algebraic Geometry · Mathematics 2007-05-23 Alexander Kuznetsov

We show that the level sets of automorphisms of free groups with respect to the Lipschitz metric are connected as subsets of Culler-Vogtmann space. In fact we prove our result in a more general setting of deformation spaces. As…

Group Theory · Mathematics 2017-03-30 Stefano Francaviglia , Armando Martino

We compute the coherent cohomology of the structure sheaf of complex periplectic Grassmannians. In particular, we show that it can be decomposed as a tensor product of the singular cohomology ring of a Grassmannian for either the symplectic…

Algebraic Geometry · Mathematics 2024-12-31 Steven V Sam , Andrew Snowden

We present a combinatorial and computational commutative algebra methodology for studying singularities of Schubert varieties of flag manifolds. We define the combinatorial notion of *interval pattern avoidance*. For "reasonable" invariants…

Algebraic Geometry · Mathematics 2008-09-13 Alexander Woo , Alexander Yong

For a semisimple adjoint algebraic group $G$ and a Borel subgroup $B$, consider the double classes $BwB$ in $G$ and their closures in the canonical compactification of $G$: we call these closures large Schubert varieties. We show that these…

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion , Patrick Polo

Let d1,...,dn be a strictly increasing sequence of integers. Boij and S\"oderberg [arXiv:math/0611081] have conjectured the existence of a graded module M of finite length over any polynomial ring K[x_1,..., x_n], whose minimal free…

Commutative Algebra · Mathematics 2012-03-13 David Eisenbud , Gunnar Floystad , Jerzy Weyman

We give a bijection between certain colored partitions and the elements in the quotient of an affine Weyl group modulo its Weyl group. By Bott's formula these colored partitions give rise to some partition identities. In certain types,…

Combinatorics · Mathematics 2008-09-28 Sara C. Billey , Stephen A. Mitchell

The Pappas-Rapoport coherence conjecture, proved by Zhu, states that the dimensions of spaces of sections of certain line bundles coincide. The two sides of the equality correspond to the line bundles on spherical Schubert varieties in the…

Representation Theory · Mathematics 2026-04-06 Evgeny Feigin , an appendix in collaboration with Andrey Karenskih

In this paper we discuss gauging noninvertible zero-form symmetries in two dimensions. We specialize to certain gaugeable cases, specifically, fusion categories of the form Rep(H) for H a suitable Hopf algebra (which includes the special…

High Energy Physics - Theory · Physics 2024-02-23 A. Perez-Lona , D. Robbins , E. Sharpe , T. Vandermeulen , X. Yu

We study the null fiber of a moment map related to dual pairs. We construct an equivariant resolution of singularities of the null fiber, and get conormal bundles of closed $ K_C $-orbits in the Lagrangian Grassmannian as the categorical…

Representation Theory · Mathematics 2010-12-16 Kyo Nishiyama

Let $G$ denote an adjoint semi-simple group over an algebraically closed field and $T$ a maximal torus of $G$. Following Contou-Carr\`ere [CC], we consider the Bott-Samelson resolution of a Schubert variety as a variety of galleries in the…

Algebraic Geometry · Mathematics 2007-05-23 Stéphane Gaussent

The motivation of this work is to construct an analog of compactified moduli of abelian varieties and toric pairs in the case of non-commutative algebraic group G. We introduce a class of "stable reductive varieties" which contain connected…

Algebraic Geometry · Mathematics 2007-05-23 Valery Alexeev , Michel Brion

Since 1976, it is known from the paper by V. P. Belkin that the variety $\mathrm{RA_2}$ of right alternative metabelian (solvable of index 2) algebras over an arbitrary field is not Spechtian (contains non-finitely based subvarieties). In…

Rings and Algebras · Mathematics 2015-02-20 Alexey Kuz'min

A permutation is called covexillary if it avoids the pattern $3412$. We construct an open embedding of a covexillary matrix Schubert variety into a Grassmannian Schubert variety. As applications of this embedding, we show that the…

Algebraic Geometry · Mathematics 2022-03-29 Rahul Singh

Restriction varieties in the orthogonal Grassmannian are subvarieties of $OG(k, n)$ defined by rank conditions given by a flag that is not necessarily isotropic with respect to the relevant symmetric bilinear form. In particular, Schubert…

Algebraic Geometry · Mathematics 2017-07-31 Seçkin Adalı

Let $P$ be a parabolic subgroup in $G=SL_n(\mathbf k)$, for $\mathbf k$ an algebraically closed field. We show that there is a $G$-stable closed subvariety of an affine Schubert variety in an affine partial flag variety which is a natural…

Algebraic Geometry · Mathematics 2022-03-29 Venkatramani Lakshmibai , Rahul Singh

We develop a new method for analyzing moduli problems related to the stack of pure coherent sheaves on a polarized family of projective schemes. It is an infinite-dimensional analogue of geometric invariant theory. We apply this to two…

Algebraic Geometry · Mathematics 2024-02-05 Daniel Halpern-Leistner , Andres Fernandez Herrero , Trevor Jones