68 citations · 116 across the 19 of their papers we have counts for
20 papers
Set-Theoretically Perfect Ideals and Residual Intersections
S. Hamid Hassanzadeh
This paper studies algebraic residual intersections in rings with Serre's condition \( S_{s} \). It demonstrates that residual intersections admit free approaches i.e. perfect subi…
Bounds on the degrees of vector fields
Marc Chardin, S. Hamid Hassanzadeh, Claudia Polini +2
In this article, we study the generalized Poincare problem from the opposite perspective, by establishing lower bounds on the degree of the vector field in terms of invariants of t…
Open loci of ideals with applications to Birational maps
S. H. Hassanzadeh, M. Mostafazadehfard
In this work we show that the loci of ideals in principal class, ideals of grade at least two, and ideals of maximal analytic spread are Zariski open sets in the parameter space. A…
Bounds for the degree and Betti sequences along a graded resolution
W. A. da Silva, S. H. Hassanzadeh, A. Simis
The main goal of this paper is to size up the minimal graded free resolution of a homogeneous ideal in terms of its generating degrees. By and large, this is too ambitious an objec…
A genus explanation of the Buchsbaum-Rim multiplicity
Vinicius Bouça, Thiago Fiel, Seyed Hamid Hassanzadeh +1
We study the Buchsbaum-Rim multiplicity, ab inicio, through a Koszul-Čech spectral sequence. We show that the Buchsbaum-Rim multiplicity is the arithmetic genus (Euler characterist…
Degree of Rational Maps versus Syzygies
M. Chardin, S. H. Hassanzadeh, A. Simis
One proves a far-reaching upper bound for the degree of a generically finite rational map between projective varieties over a base field of arbitrary characteristic. The bound is e…
Residual Intersections are Koszul-Fitting ideals
Vinicius Bouça, Seyed Hamid Hassanzadeh
One describes generators of disguised residual intersections in any commutative Noetherian rings. It is shown that, over Cohen-Macaulay rings, the disguised residual intersections…
Koszul Algebras Defined by Three Relations
Adam Boocher, S. Hamid Hassanzadeh, Srikanth B. Iyengar
This work concerns commutative algebras of the form , where is a standard graded polynomial ring and is a homogenous ideal in . It has been proposed that when …
Effective criteria for bigraded birational maps
Nicolás Botbol, Laurent Busé, Marc Chardin +3
In this paper, we consider rational maps whose source is a product of two subvarieties, each one being embedded in a projective space. Our main objective is to investigate biration…
Bounds on the degrees of birational maps with arithmetically Cohen-Macaulay graphs
S. Hamid Hassanzadeh, Aron Simis
A rational map whose source and image are projectively embedded varieties has an {\em Arithmetically Cohen-Macaulay graph} if the Rees algebra of one (hence any) of its base ideals…
Residual Intersections and the Annihilator of Koszul Homologies
S. H. Hassanzadeh, J. Naéliton
Cohen-Macaulayness, unmixedness, the structure of the canonical module and the stability of the Hilbert function of algebraic residual intersections are studied in this paper. Some…
Implicitization of de Jonquières parametrizations
Seyed Hamid Hassanzadeh, Aron Simis
One introduces a class of projective parameterizations that resemble generalized de Jonquières maps. Any such parametrization defines a birational map of $\pp^n$ ont…
Plane Cremona maps: saturation and regularity of the base ideal
S. H. Hassanzadeh, A. Simis
One studies plane Cremona maps by focusing on the ideal theoretic and homological properties of its homogeneous base ideal ("indeterminacy locus"). The {\em leitmotiv} driving a go…
A characteristic free criterion of birationality
A. V. Dória, S. H. Hassanzadeh, A. Simis
One develops {\em ab initio} the theory of rational/birational maps over reduced, but not necessarily irreducible, projective varieties in arbitrary characteristic. A numerical inv…
Linkage of modules over Cohen-Macaulay rings
Mohammad T. Dibaei, Mohsen Gheibi, S. H. Hassanzadeh +1
Inspired by the works in linkage theory of ideals, the concept of sliding depth of extension modules is defined to prove the Cohen-Macaulyness of linked module if the base ring is…
A note on the regularity of products
Seyed Hamid Hassanzadeh, Siamak Yassemi
Let denote a polynomial ring over a field . Given a monomial ideal and a finitely generated multigraded over , we follow Herzog's met…
Ideals Whose First Two Betti Numbers are Close
Keivan Borna, S. H. Hassanzadeh
For an ideal of a Noetherian local ring $(R,\fm,k)$ we show that $\bt_1^R(I)-\bt_0^R(I)\geq -1$. It is demonstrated that some residual intersections of an ideal for which $…
Cohen-Macaulay residual intersections and their Castelnuovo-Mumford Regularity
Seyed Hamid Hassanzadeh
In this article we study the structure of residual intersections via constructing a finite complex which is acyclic under some sliding depth conditions on the cycles of the Koszul…
On Vanishing and Cofiniteness of Generalized Local Cohomology Modules
S. H. Hassanzadeh, A. Vahidi
In this paper, some results on vanishing and non-vanishing of generalized local cohomology modules are presented and some relations between those modules and, Ext and ordinary loca…
A note on quasi-Gorenstein rings
S. H. Hassanzadeh, N. Shirmohammadi, H. Zakeri
In this paper, after giving a criterion for a Noetherian local ring to be quasi-Gorenstein, we obtain some sufficient conditions for a quasi- Gorenstein ring to be Gorenstein. In t…