11 papers
CI-sequences and almost complete intersections
Giuseppe Zappalà
We study the Hilbert function and the graded Betti numbers of almost complete intersection artinian algebras. We show that that every Hilbert function of a complete intersection ar…
On minimal Gorenstein Hilbert function
Lenin Bezerra, Rodrigo Gondim, Giovanna Ilardi +1
We conjecture that a class of Artinian Gorenstein Hilbert algebras called full Perazzo algebras always have minimal Hilbert function, fixing codimension and length. We prove the co…
Properties of the resolution of almost Gorenstein algebras
Giuseppe Zappalà
We study properties of the resolution of almost Gorenstein artinian algebras i.e. algebras defined by ideals such that with Gorenstein ideal and …
On mixed Hessians and the Lefschetz properties
Rodrigo Gondim, Giuseppe Zappala'
We introduce a new type of Hessian matrix, that we call Mixed Hessian. The mixed Hessian is used to compute the rank of a multiplication map by a power of a linear form in a standa…
Minimal free resolutions for homogeneous ideals with Betti numbers
Alfio Ragusa, Giuseppe Zappalà
We investigate the standard generalized Gorenstein algebras of homological dimension three, giving a structure theorem for their resolutions. Moreover in many cases we are able to…
Lefschetz properties for Artinian Gorenstein algebras presented by quadrics
Rodrigo Gondim, Giuseppe Zappalà
We introduce a family of standard bigraded binomial Artinian Gorenstein algebras, whose combinatoric structure characterizes the ones presented by quadrics. These algebras provide,…
Tower sets and other configurations with the Cohen-Macaulay property
Giuseppe Favacchio, Alfio Ragusa, Giuseppe Zappalà
Some well-known arithmetically Cohen-Macaulay configurations of linear varieties in as -configurations, partial intersections and star configurations are generali…
A structure theorem for unions of complete intersections
Alfio Ragusa, Giuseppe Zappala
Using the connections among almost complete intersection schemes, arithmetically Gorenstein schemes and schemes that are union of complete intersections we give a structure theorem…
On the Weak-Lefschetz property for Artinian Gorenstein algebras
Alfio Ragusa, Giuseppe Zappala
We deal with the Weak Lefschetz property (WLP) for Artinian standard graded Gorenstein algebras of codimension We prove that many Gorenstein sequences force the WLP for such a…
On the Weak Lefschetz Property for Hilbert functions of almost complete intersections
Alfio Ragusa, Giuseppe Zappala
It is known that all complete intersection Artinian standard graded algebras of codimension 3 have the Weak Lefschetz Property. Unfortunately, this property does not continue to be…
A Structure Theorem and the Graded Betti Numbers for Almost Complete Intersections
Alfio Ragusa, Giuseppe Zappala
We provide a structure theorem for all almost complete intersection ideals of depth three in any Noetherian local ring. In particular, we find that the minimal generators are the p…