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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

We consider a class of semidirect products $G = \mathbb{R}^n \rtimes H$, with $H$ a suitably chosen abelian matrix group. The choice of $H$ ensures that there is a wavelet inversion formula, and we are looking for criteria to decide under…

Representation Theory · Mathematics 2015-07-13 Bradley Currey , Hartmut Führ , Keith Taylor

We establish an explicit embedding of a quantum affine $\mathfrak{sl}_n$ into a quantum affine $\mathfrak{sl}_{n+1}$. This embedding serves as a common generalization of two natural, but seemingly unrelated, embeddings, one on the quantum…

Quantum Algebra · Mathematics 2022-08-17 Yiqiang Li

We describe a closed immersion from each representation space of a type A quiver with bipartite (i.e., alternating) orientation to a certain opposite Schubert cell of a partial flag variety. This "bipartite Zelevinsky map" restricts to an…

Algebraic Geometry · Mathematics 2015-09-18 Ryan Kinser , Jenna Rajchgot

We study the combinatorics of Gr\"obner degenerations of Grassmannians and the Schubert varieties inside them. We provide a family of binomial ideals whose combinatorics is governed by tableaux induced by matching fields in the sense of…

Commutative Algebra · Mathematics 2020-09-15 Oliver Clarke , Fatemeh Mohammadi

In this paper we study the Grassmannian of submodules of a given dimension inside a finitely generated projective module $P$ for a finite dimensional algebra $\Lambda$ over an algebraically closed field. The orbit of such a submodule $C$…

Representation Theory · Mathematics 2017-08-10 Frauke M. Bleher , Ted Chinburg , Birge Huisgen-Zimmermann

Let $H$ be a finite dimensional pointed rank one Hopf algebra of nilpotent type. We first determine all finite dimensional indecomposable $H$-modules up to isomorphism, and then establish the Clebsch-Gordan formulas for the decompositions…

Representation Theory · Mathematics 2013-09-10 Zhihua Wang , Libin Li , Yinhuo Zhang

Knutson and Miller (2005) established a connection between the anti-diagonal Gr\"obner degenerations of matrix Schubert varieties and the pre-existing combinatorics of pipe dreams. They used this correspondence to give a…

Commutative Algebra · Mathematics 2023-01-19 Patricia Klein

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

We introduce a Grassmannian structure for a class of quotient Hilbert modules and attack the polydisc version of Arveson-Douglas conjecture associated to distinguished varieties. More interestingly, we obtain an operator-theoretic…

Operator Algebras · Mathematics 2023-04-27 Kunyu Guo , Penghui Wang , Chong Zhao

Using combinatorial properties of symmetric polynomials, we compute explicitly the Soergel modules for some permutations whose corresponding Schubert varieties are rationally smooth. We build from them diagram algebras whose module…

Representation Theory · Mathematics 2013-11-28 Antonio Sartori

We give a complete list of smooth and rationally smooth normalized Schubert varieties in the twisted affine Grassmannian associated with a tamely ramified group and a special vertex of its Bruhat-Tits building. The particular case of the…

Algebraic Geometry · Mathematics 2020-12-23 Thomas J. Haines , Timo Richarz

We obtain tight bounds for the minimal number of generators of an ideal with bounded-degree generators in a polynomial ring $K[X_1,\dots,X_n],$ as well as a sharp quantification of the maximum possible size of a minimal generating set of…

Commutative Algebra · Mathematics 2025-09-23 Andrei Mandelshtam

We build generalizations of the Grassmann algebras from a few simple assumptions which are that they are graded, maximally symmetric and contain an ordinary Grassmann algebra as a subalgebra. These algebras are graded by Z_{n}^{3} and…

High Energy Physics - Theory · Physics 2009-10-30 Bertrand Le Roy

We study Hilbert-Samuel multiplicity for points of Schubert varieties in the complete flag variety, by Groebner degenerations of the Kazhdan-Lusztig ideal. In the covexillary case, we give a positive combinatorial rule for multiplicity by…

Algebraic Geometry · Mathematics 2011-11-08 Li Li , Alexander Yong

It is well known that the ring of polynomial invariants of a reductive group is finitely generated. However, it is difficult to give strong upper bounds on the degrees of the generators, especially over fields of positive characteristic. In…

Representation Theory · Mathematics 2016-10-24 Harm Derksen , Visu Makam

We show that the apolar ideals to the determinant and permanent of a generic matrix, the Pfaffian of a generic skew symmetric matrix and the Hafnian of a generic symmetric matrix are each generated in degree two. In each case we specify the…

Commutative Algebra · Mathematics 2013-03-26 Masoumeh Sepideh Shafiei

We describe how each finite dimensional Schubert cell in the affine flag variety of $\text{SL}_2$ decomposes into orbits for a chain of subgroups of codimension one to four of the Iwahori group.

Algebraic Geometry · Mathematics 2026-05-14 Claude Eicher

We provide two alternate settings for a family of varieties modeling the uniserial representations with fixed sequence of composition factors over a finite dimensional algebra. The first is a quasi-projective subvariety of a Grassmannian…

Representation Theory · Mathematics 2014-07-10 Klaus Bongartz , Birge Huisgen-Zimmermann

In this paper, we study the subvarieties of a complex flag variety that are invariant under the action of a maximal torus. Using combinatorial techniques derived from matroid theory, we introduce a decomposition of this variety into affine,…