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Let X be a projective variety, $\sigma$ an automorphism of X, L a $\sigma$-ample invertible sheaf on X, and Z a closed subscheme of X. Inside the twisted homogeneous coordinate ring $B = B(X, L, \sigma)$, let I be the right ideal of…

Rings and Algebras · Mathematics 2010-09-07 Susan J. Sierra

We determine which tangential varieties of homogeneously embedded rational homogeneous varieties are spherical. We determine the homogeneous coordinate rings and rings of covariants of the tangential varieties of homogenously embedded…

Algebraic Geometry · Mathematics 2007-05-23 J. M. Landsberg , Jerzy Weyman

Let $X$ be an algebraic variety such that the group $\text{Aut}(X)$ acts on $X$ transitively. We define the transitivity degree of $X$ as a maximal number $m$ such that the action of $\text{Aut}(X)$ on $X$ is $m$-transitive. If the action…

Algebraic Geometry · Mathematics 2022-11-08 Ivan Arzhantsev , Kirill Shakhmatov , Yulia Zaitseva

The Cox ring provides a coordinate system on a toric variety analogous to the homogeneous coordinate ring of projective space. Rational maps between projective spaces are described using polynomials in the coordinate ring, and we generalise…

Algebraic Geometry · Mathematics 2014-06-02 Gavin Brown , Jarosław Buczyński

Given a semi-algebraic set S, we study compactifications of S that arise from embeddings into complete toric varieties. This makes it possible to describe the asymptotic growth of polynomial functions on S in terms of combinatorial data. We…

Algebraic Geometry · Mathematics 2017-05-17 Daniel Plaumann , Claus Scheiderer

Let V be a normal affine variety over the real numbers R, and let S be a semi-algebraic subset of V(R). We study the subring B(S) of the coordinate ring of V consisting of the polynomials that are bounded on S. We introduce the notion of…

Algebraic Geometry · Mathematics 2010-07-30 Daniel Plaumann , Claus Scheiderer

We present a class of homogeneous ideals which are generated by monomials and binomials of degree two and are set-theoretic complete intersections. This class includes certain reducible varieties of minimal degree and, in particular, the…

Algebraic Geometry · Mathematics 2007-06-28 Margherita Barile

In this work, we extend Saia's results on the characterization of Newton non-degenerate ideals to the context of ideals in $O_{X(S)}$, where $X(S)$ is an affine toric variety defined by the semigroup $S\subset \mathbb{Z}^{n}_{+}$. We…

Algebraic Geometry · Mathematics 2025-05-13 Amanda S. Araújo , Thaís M. Dalbelo , Thiago da Silva

A non-degenerate toric variety $X$ is called $S$-homogeneous if the subgroup of the automorphism group $\text{Aut}(X)$ generated by root subgroups acts on $X$ transitively. We prove that maximal $S$-homogeneous toric varieties are in…

Algebraic Geometry · Mathematics 2018-04-24 Ivan Arzhantsev

Let $X_{\Sigma}$ be a smooth complete toric variety defined by a fan $\Sigma$ and let $V=V(I)$ be a subscheme of $X_{\Sigma}$ defined by an ideal $I$ homogeneous with respect to the grading on the total coordinate ring of $X_{\Sigma}$. We…

Algebraic Geometry · Mathematics 2017-11-15 Martin Helmer

We study polynomial systems with prescribed monomial supports in the Cox rings of toric varieties built from complete polyhedral fans. We present combinatorial formulas for the dimensions of their associated subvarieties under genericity…

Symbolic Computation · Computer Science 2024-02-21 Matías Bender , Pierre-Jean Spaenlehauer

In this paper, we prove that if $P$ is a homogeneous prime ideal inside a standard graded polynomial ring $S$ with $\dim(S/P)=d$, and for $s \leq d$, adjoining $s$ general linear forms to the prime ideal changes the $(d-s)$-th Hilbert…

Commutative Algebra · Mathematics 2025-01-15 Cheng Meng

Let $R$ be a standard graded polynomial ring that is finitely generated over a field of characteristic $0$, let $\mathfrak{m}$ be the homogeneous maximal ideal of $R$, and let $I$ be a homogeneous prime ideal of $R$. Dao and Monta\~{n}o…

Commutative Algebra · Mathematics 2019-12-12 Jennifer Kenkel

We present examples which show that in dimension higher than one or codimension higher than two, there exist toric ideals I_A such that no binomial ideal contained in I_A and of the same dimension is a complete intersection. This result has…

Commutative Algebra · Mathematics 2007-05-23 Eduardo Cattani , Raymond Curran , Alicia Dickenstein

Toric quiver varieties (moduli spaces of quiver representations) are studied. Given a quiver and a weight there is an associated quasiprojective toric variety together with a canonical embedding into projective space. It is shown that for a…

Representation Theory · Mathematics 2014-02-21 M. Domokos , Dániel Joó

The paper deals with a complex polynomial $H$ in two variables having - a generic highest homogeneous part (without multiple zero lines), - nonconstant lower terms. In particular, under these conditions the polynomial $H$ has at least two…

Algebraic Geometry · Mathematics 2007-05-23 Alexey Glutsyuk

We describe the construction of a class of toric varieties as spectra of homogeneous prime ideals.

Algebraic Geometry · Mathematics 2009-08-06 Markus Perling

Let $R=k[x,y,z]$ be a standard graded $3$-variable polynomial ring, where $k$ denotes any field. We study grade $3$ homogeneous ideals $I \subseteq R$ defining compressed rings with socle $k(-s)^{\ell} \oplus k(-2s+1)$, where $s \geq3$ and…

Commutative Algebra · Mathematics 2021-05-28 Keller VandeBogert

We present a new eigenvalue method for solving a system of Laurent polynomial equations defining a zero-dimensional reduced subscheme of a toric compactification $X$ of $(\mathbb{C} \setminus \{0\})^n$. We homogenize the input equations to…

Algebraic Geometry · Mathematics 2020-02-13 Simon Telen

In this paper, we investigate the structure of the saturation of ideals generated by sparse homogeneous polynomials over a projective toric variety $X$ with respect to the irrelevant ideal of $X$. As our main results, we establish a duality…

Algebraic Geometry · Mathematics 2024-05-28 Laurent Busé , Carles Checa