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We provide necessary and sufficient conditions for simplicial complexes whose determinantal facet ideals admit reduced Grobner bases under diagonal term orders. Building on and extending foundational results for binomial edge ideals and…

Commutative Algebra · Mathematics 2026-01-27 Fahimeh Khosh-Ahang Ghasr

In this paper we show that determinantal ideals of generic matrices are Knutson ideals. This fact leads to a useful result about Gr\"obner bases of certain sums of determinantal ideals. More specifically, given $I=I_1+\ldots+I_k$ a sum of…

Commutative Algebra · Mathematics 2021-01-19 Lisa Seccia

We prove a criterion for the normality of Schubert varieties in twisted affine Grassmannians in terms of the order of the algebraic fundamental group of a certain Levi subgroup, in particular in small positive characteristic. As an…

Algebraic Geometry · Mathematics 2025-10-07 Patrick Bieker

A set of polynomials G in a polynomial ring S over a field is said to be a universal Groebner basis, if G is a Groebner basis with respect to every term order on S. Twenty years ago Bernstein, Sturmfels, and Zelevinsky proved that the set…

Commutative Algebra · Mathematics 2013-02-26 Aldo Conca , Emanuela De Negri , Elisa Gorla

The Specht ideal of shape $\lambda$, where $\lambda$ is a partition, is the ideal generated by all Specht polynomials of shape $\lambda$. Haiman and Woo proved that these ideals are reduced and found their universal Gr\"obner bases. In this…

Commutative Algebra · Mathematics 2021-11-11 Satoshi Murai , Hidefumi Ohsugi , Kohji Yanagawa

Matrix Schubert varieties are certain varieties in the affine space of square matrices which are determined by specifying rank conditions on submatrices. We study these varieties for generic matrices, symmetric matrices, and upper…

Algebraic Geometry · Mathematics 2016-09-14 Alex Fink , Jenna Rajchgot , Seth Sullivant

We address the problem of defining Schubert classes independently of a reduced word in equivariant elliptic cohomology, based on the Kazhdan-Lusztig basis of a corresponding Hecke algebra. We study some basic properties of these classes,…

Algebraic Geometry · Mathematics 2016-02-09 Cristian Lenart , Kirill Zainoulline

In this paper, we survey the theory of Cartwright-Sturmfels ideals. These are Z^n-graded ideals, whose multigraded generic initial ideal is radical. Cartwright-Sturmfels ideals have surprising properties, mostly stemming from the fact that…

Commutative Algebra · Mathematics 2021-08-24 A. Conca , E. De Negri , E. Gorla

We study quantum Schubert varieties from the point of view of regularity conditions. More precisely, we show that these rings are domains which are maximal orders and are AS-Cohen-Macaulay and we determine which of them are AS-Gorenstein.…

Quantum Algebra · Mathematics 2007-05-23 T H Lenagan , L Rigal

We study an inductive method of computing initial ideals and Gr\"obner bases for families of ideals in a polynomial ring. This method starts from a given set of pairs $(I,J)$ where $I$ is any ideal and $J$ is a monomial ideal contained in…

Commutative Algebra · Mathematics 2026-01-28 Eric Marberg , Brendan Pawlowski

This chapter combines an introduction and research survey about Schubert varieties. The theme is to combinatorially classify their singularities using a family of polynomial ideals generated by determinants.

Algebraic Geometry · Mathematics 2023-03-03 Alexander Woo , Alexander Yong

Nakajima's graded quiver varieties naturally appear in the study of bases of cluster algebras. One particular family of these varieties, namely the bipartite determinantal varieties, can be defined for any bipartite quiver and gives a vast…

Commutative Algebra · Mathematics 2024-06-25 Josua Illian , Li Li

Let G be a simply-connected simple compact Lie group over the complex numbers. The affine Grassmannian is a projective ind-variety, homotopy-equivalent to the loop space of G and closely analogous to a maximal flag variety of the classical…

Algebraic Geometry · Mathematics 2007-12-19 Sara C. Billey , Stephen A. Mitchell

In this paper, we give a sufficient condition for a set $\mathal G$ of polynomials to be a Gr\"obner basis with respect to a given term-order for the ideal $I$ that it generates. Our criterion depends on the linkage pattern of the ideal $I$…

Commutative Algebra · Mathematics 2011-06-06 Elisa Gorla , Juan C. Migliore , Uwe Nagel

Patch ideals encode neighbourhoods of a variety in GL_n/B. For Peterson varieties we determine generators for these ideals and show they are complete intersections, and thus Cohen-Macaulay and Gorenstein. Consequently, we combinatorially…

Algebraic Geometry · Mathematics 2012-11-30 Erik Insko , Alexander Yong

Let $G$ be a simple algebraic group of adjoint type of rank $n$ over $\mathbb{C}$. Let $T$ be a maximal torus of $G$, and $B$ be a Borel subgroup of $G$ containing $T$. Let $W=N_{G}(T)/T$ be the Weyl group of $G$. Let…

Algebraic Geometry · Mathematics 2024-01-24 Arkadev Ghosh , S. S. Kannan

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

The homogeneous coordinate ring of a Schubert variety (a Schubert cycle for short) is an algebra with straightening law generated by a distributive lattice. This paper gives a simple method to study the set of all the join-irreducible…

Commutative Algebra · Mathematics 2007-05-23 Mitsuhiro Miyazaki

We classify all normal Schubert varieties in the affine Grassmannian of a semisimple group over an arbitrary field with special attention to small positive characteristic. The proof is elementary and relies on tangent space calculations for…

Algebraic Geometry · Mathematics 2025-07-10 Patrick Bieker , Timo Richarz

We compute the initial ideals, with respect to certain conveniently chosen term orders, of ideals of tangent cones at torus fixed points to Schubert varieties in orthogonal Grassmannians. The initial ideals turn out to be square-free…

Combinatorics · Mathematics 2008-03-16 K. N. Raghavan , Shyamashree Upadhyay