arXiv subjects

Jung Pil Park

Publications and source records attributed to Jung Pil Park.

4 recordsLinked to original sources

arXiv2014

The Minimal Free Resolution of A Star-Configuration in $\mathbb{P}^n$

We find the minimal free resolution of the ideal of a star-configuration in $\mathbb{P}^n$ of type $(r,s)$ defined by general forms in $R=\Bbbk[x_0,x_1,\dots,x_n]$. This generalises the results of \cite{AS:1,GHM} from a specific value of $r=2$ to any value of $1\le r\le n$. Moreover, we show that any star-configuration in $\mathbb{P}^n$ is arithmetically Cohen-Macaulay. As an application, we construct a few of graded Artinian rings, which have the weak Lefschetz property, using the sum of two ideals of star-configurations in $\mathbb{P}^n$.

math.AC↗

arXiv2009

Almost reverse lexicographic ideals and Fröberg sequence

We study almost reverse lexicographic ideals in a polynomial ring over a field of arbitrary characteristic. We give a criterion for a given sequence of nonnegative integers to be the Hilbert function of an almost reverse lexicographic ideal in the polynomial ring. Then it will be shown that every Fröberg sequence satisfies this criterion.

math.AC↗

arXiv2007

Conditions for Generic Initial Ideals to be Almost Reverse Lexicographic

Let $I$ be a homogeneous Artinian ideal in a polynomial ring $R=k[x_1,...,x_n]$ over a field $k$ of characteristic 0. We study an equivalent condition for the generic initial ideal $\gin(I)$ with respect to reverse lexicographic order to be almost reverse lexicographic. As a result, we show that Moreno-Socias conjecture implies Fröberg conjecture. And for the case $\Codim I \le 3$, we show that $R/I$ has the strong Lefschetz property if and only if $\gin(I)$ is almost reverse lexicographic. Finally for a monomial complete intersection Artinian ideal $I=(x_1^{d_1},...,x_n^{d_n})$, we prove that $\gin(I)$ is almost reverse lexicographic if $d_i > \sum_{j=1}^{i-1} d_j - i + 1$ for each $i \ge 4$. Using this, we give a positive partial answer to Moreno-Socias conjecture, and to Fröberg conjecture.

math.AC↗

arXiv2006

Generic Initial Ideals of Artinian Ideals Having Lefschetz Properties or The Strong Stanley Property

For a standard Artinian $k$-algebra $A=R/I$, we give equivalent conditions for $A$ to have the weak (or strong) Lefschetz property or the strong Stanley property in terms of the minimal system of generators of the generic initial ideal $\mathrm{gin}(I)$ of $I$ under the reverse lexicographic order. Using the equivalent condition for the weak Lefschetz property, we show that some graded Betti numbers of $\mathrm{gin}(I)$ are determined just by the the Hilbert function of $I$ if $A$ has the weak Lefschetz property. Furthermore, for the case that $A$ is a standard Artinian $k$-algebra of codimension 3, we show that every graded Betti numbers of $\mathrm{gin}(I)$ are determined by the graded Betti numbers of $I$ if $A$ has the weak Lefschetz property. And if $A$ has the strong Lefschetz (resp. Stanley) property, then we show that the minimal system of generators of $\mathrm{gin}(I)$ is determined by the graded Betti numbers (resp. by the Hilbert function) of $I$.

math.AC↗