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Comparing powers and symbolic powers of ideals

Author(s): Cristiano Bocci; Brian Harbourne
Journal: J. Algebraic Geom.
Posted: August 17, 2009
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Abstract | References | Additional information

Abstract: We develop tools to study the problem of containment of symbolic powers $ I^{(m)}$ in powers $ I^r$ for a homogeneous ideal $ I$ in a polynomial ring $ k[{\bf P}^N]$ in $ N+1$ variables over an arbitrary algebraically closed field $ k$. We obtain results on the structure of the set of pairs $ (r,m)$ such that $ I^{(m)}\subseteq I^r$. As corollaries, we show that $ I^2$ contains $ I^{(3)}$ whenever $ S$ is a finite generic set of points in $ {\bf P}^2$ (thereby giving a partial answer to a question of Huneke), and we show that the containment theorems of

Ein-Lazarsfeld-Smith [Invent. Math. 144 (2001), pp. 241-252] and

Hochster-Huneke [Invent. Math. 147 (2002), pp. 349-369] are optimal for every fixed dimension and codimension.

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Additional Information:

Cristiano Bocci
Affiliation: Dipartimento di Scienze Matematiche e Informatiche ``R. Magari'', Università degli Studi di Siena, Pian dei mantellini, 44, 53100 Siena, Italy
Email: bocci24@unisi.it

Brian Harbourne
Affiliation: Department of Mathematics, University of Nebraska, Lincoln, Nebraska 68588-0130
Email: bharbour@math.unl.edu

PII: S 1056-3911(09)00530-X
Received by editor(s): February 12, 2008
Posted: August 17, 2009
Additional Notes: This reseach was partially supported by Gruppo Nazionale per le Strutture Algebriche, Geometriche e le loro Applicazioni of Istituto Nazionale di Alta Matematica (Italy) and by the National Security Agency

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