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Shahriyar Roshan-Zamir

Publications and source records attributed to Shahriyar Roshan-Zamir.

2 recordsLinked to original sources

On the algebraic properties of the Böröczky configuration

The Böröczky configuration of lines and (multiple) points exhibits extremal behavior in commutative algebra and combinatorics. Examples of this appear in the context of the containment problem for ordinary and symbolic powers and the proof of the Dirac-Motzkin conjecture by Green and Tao. This paper studies the algebraic properties of Böröczky configurations for arbitrary values of $n$. Our results compute the Waldschmit constant of the defining ideal of these configurations. Moreover, we use the weighted projective plane $\mathbb{P}(1,2,3)$ to give an upper bound for the degree of the minimal generators of their ideal. Finally, this construction is applied to an elliptic curve in $\mathbb{P}^2$ to give a new counterexample to the containment $I^{(3)}\subseteq I^2$.

math.AC↗

Interpolation in Weighted Projective Spaces

Over an algebraically closed field, the $\textit{double point interpolation}$ problem asks for the vector space dimension of the projective hypersurfaces of degree $d$ singular at a given set of points. After being open for 90 years, a series of papers by J. Alexander and A. Hirschowitz in 1992--1995 settled this question in what is referred to as the Alexander-Hirschowitz theorem. In this paper we primarily use commutative algebra to lay the groundwork necessary to prove analogous statements in the $\textit{weighted projective space}$, a natural generalization of the projective space. We show the Hilbert function of general simple points in any $n$-dimensional weighted projective space exhibits the expected behavior. We give an inductive procedure for weighted projective space, similar to that originally due to A. Terracini from 1915, to demonstrate an example of a weighted projective plane where the analogue of the Alexander-Hirschowitz theorem holds without exceptions. We further adapt Terracini's lemma regarding secant varieties to give an interpolation bound for an infinite family of weighted projective planes.

math.AC↗