An Elementary Approach to Containment Relations Between Symbolic and Ordinary Powers of Certain Monomial Ideals
| Autor: | Ryan W. Keane, Elise McMahon, Alex Küronya |
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| Rok vydání: | 2015 |
| Předmět: |
Class (set theory)
Containment (computer programming) Monomial Algebra and Number Theory Mathematics::Commutative Algebra 010102 general mathematics Mathematics - Commutative Algebra Commutative Algebra (math.AC) 14C99 13C05 01 natural sciences Algebra Mathematics - Algebraic Geometry Simple (abstract algebra) 0103 physical sciences FOS: Mathematics 010307 mathematical physics 0101 mathematics Algebraic Geometry (math.AG) Mathematics |
| DOI: | 10.48550/arxiv.1512.07092 |
| Popis: | The purpose of this note is to find an elemenary explanation of a surprising result of Ein--Lazarsfeld--Smith \cite{ELS} and Hochster--Huneke \cite{HH} on the containment between symbolic and ordinary powers of ideals in simple cases. This line of research has been very active ever since, see for instance \cites{BC,HaH,DST} and the references therein, by now the literature on this topic is quite extensive. By `elementary' we refer to arguments that among others do not make use of resolution of singularities and multiplier ideals nor tight closure methods. Let us quickly recall the statement \cite{ELS}: let $X$ be a smooth projective variety of dimension $n$, $S \subseteq O_X$ a non-zero sheaf of radical ideals with zero scheme $Z\subseteq X$; if every irreducible component of $Z$ has codimension at least $e$, then \[ S^{(me)}_Z \subseteq S^m_Z \] for all $m\geq 1$. Our goal is to reprove this assertion in the case of points in projective spaces (as asked in \cite{PAGII}*{Example 11.3.5}) without recurring to deep methods of algebraic geometry. Instead of working with subsets of projective space, we will concentrate on the affine cones over them; our aim hence becomes to understand symbolic and ordinary powers ideals of sets of line through the origin. We will end up reducing the general case to a study of the ideals \[ I_{2,n} =(x_ix_j\mid 1\leq i Comment: 5 pages |
| Databáze: | OpenAIRE |
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