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We consider the multigraded Hilbert scheme corresponding to the Hilbert function of a finite number of points in general position in a smooth projective complex toric variety. We develop several criteria for a point of that parameter space…

Algebraic Geometry · Mathematics 2023-06-16 Tomasz Mańdziuk

Using results obtained from the study of homogeneous ideals sharing the same initial ideal with respect to some term order, we prove the singularity of the point corresponding to a segment ideal with respect to the revlex term order in the…

Commutative Algebra · Mathematics 2010-03-16 Francesca Cioffi , Paolo Lella , Maria Grazia Marinari , Margherita Roggero

Borel-fixed ideals play a key role in the study of Hilbert schemes. Indeed each component and each intersection of components of a Hilbert scheme contains at least one Borel-fixed point, i.e. a point corresponding to a subscheme defined by…

Symbolic Computation · Computer Science 2012-05-03 Paolo Lella

In order to determine the Hilbert function of the ideal of a fat point subscheme of projective space, we show that it is enough to determine, both for the subscheme itself and the subschemes obtained from it by successively adjoining to it…

Algebraic Geometry · Mathematics 2007-05-23 Brian Harbourne

We investigate the defining ideal of a set of points X in multi-projective space with a special emphasis on the case that X is in generic position, that is, X has the maximal Hilbert function. When X is in generic position, we determine the…

Commutative Algebra · Mathematics 2007-05-23 Adam Van Tuyl

We determine the Hilbert series of some classes of ideals generated by generic forms of degree two and three, and investigate the difference to the Hilbert series of ideals generated by powers of linear generic forms of the corresponding…

Commutative Algebra · Mathematics 2024-10-03 Ralf Froberg

We develop sampling formulas for high-dimensional functions in reproducing kernel Hilbert spaces, where we rely on irregular samples that are taken at determining sequences of data points. We place particular emphasis on sampling formulas…

Machine Learning · Computer Science 2025-04-21 Armin Iske , Lennart Ohlsen

An ideal of a local polynomial ring can be described by calculating a standard basis with respect to a local monomial ordering. However standard basis algorithms are not numerically stable. Instead we can describe the ideal numerically by…

Algebraic Geometry · Mathematics 2012-11-22 Robert Krone

The diagonal in a product of projective spaces is cut out by the ideal of 2x2-minors of a matrix of unknowns. The multigraded Hilbert scheme which classifies its degenerations has a unique Borel-fixed ideal. This Hilbert scheme is generally…

Algebraic Geometry · Mathematics 2009-08-27 Dustin Cartwright , Bernd Sturmfels

Toric ideals to hierarchical models are invariant under the action of a product of symmetric groups. Taking the number of factors, say m, into account, we introduce and study invariant filtrations and their equivariant Hilbert series. We…

Commutative Algebra · Mathematics 2021-04-21 Aida Maraj , Uwe Nagel

Reduced ideals have been defined in the context of integer rings in quadratic number fields, and they are closely tied to the continued fraction algorithm. The notion of this type of ideal extends naturally to number fields of higher…

Number Theory · Mathematics 2019-06-04 George Jacobs

Let $\mathfrak a$ be an ideal of holomorphic functions vanishing only at the origin in $\mathbb{C}^n$. The \textit{type} of $\mathfrak a$ is an invariant that measures the order of vanishing of the functions in $\mathfrak a$ along…

Complex Variables · Mathematics 2007-05-23 Gordon Heier , Robert Lazarsfeld

Bounds for the Castelnuovo-Mumford regularity and Hilbert coefficients are given in terms of the arithmetic degree (if the ring is reduced) or in terms of the defining degrees. From this it follows that there exists only a finite number of…

Commutative Algebra · Mathematics 2018-09-21 Lê Tuân Hoa

Given a finite set, $X$, of points in projective space for which the Hilbert function is known, a standard result says that there exists a subset of this finite set whose Hilbert function is ``as big as possible'' inside $X$. Given a finite…

Algebraic Geometry · Mathematics 2007-05-23 Steven P. Diaz , Anthony V. Geramita , Juan C. Migliore

The aim of this work is to reduce the complexity of the available algorithms for computing the generator sets of a semigroup ideal by using the Hermite normal form. In order to achieve it we introduce the concept of decomposable semigroup.…

Commutative Algebra · Mathematics 2013-08-09 Juan Ignacio García-García , M. Ángeles Moreno-Frías , Alberto Vigneron-Tenorio

We associate to each $r$-multigraded, locally finitely generated ideal in the "large polynomial ring" on countably many indeterminates a power series in $r$ variables; this power series is the limit in the adic topology of the numerators of…

Commutative Algebra · Mathematics 2007-05-23 Jan Snellman

We study the normalization of a monomial ideal, and show how to compute its Hilbert function (using Ehrhart polynomials) if the ideal is zero dimensional. A positive lower bound for the second coefficient of the Hilbert polynomial is shown.

Commutative Algebra · Mathematics 2011-03-11 Rafael H. Villarreal

The equivariant Hilbert series of an ideal generated by an orbit of a monomial under the action of the monoid $\mbox{Inc}(\mathbb{N})$ of strictly increasing functions is determined. This is used to find the dimension and degree of such an…

Commutative Algebra · Mathematics 2016-08-24 Sema Gunturkun , Uwe Nagel

Let $R^h$ denote the polynomial ring in variables $x_1,\,\ldots,\, x_h$ over a specified field $K$. We consider all of these rings simultaneously, and in each use lexicographic (lex) monomial order with $x_1 > \cdots > x_h$. Given a fixed…

Commutative Algebra · Mathematics 2020-03-03 Tigran Ananyan , Melvin Hochster

In this paper, we present a modular strategy which describes key properties of the absolute primary decomposition of an equidimensional polynomial ideal defined by polynomials with rational coefficients. The algorithm we design is based on…

Commutative Algebra · Mathematics 2010-12-24 Cristina Bertone
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