Generalized k-Configurations

Sabourin, Sindi

Canadian journal of mathematics, Tome 57 (2005) no. 2, pp. 400-415

Résumé

In this paper, we find configurations of points in $n$ -dimensional projective space $\left( {{\mathbb{P}}^{n}} \right)$ which simultaneously generalize both $k$ -configurations and reduced 0-dimensional complete intersections. Recall that $k$ -configurations in ${{\mathbb{P}}^{2}}$ are disjoint unions of distinct points on lines and in ${{\mathbb{P}}^{n}}$ are inductively disjoint unions of $k$ -configurations on hyperplanes, subject to certain conditions. Furthermore, the Hilbert function of a $k$ -configuration is determined from those of the smaller $k$ -configurations. We call our generalized constructions ${{k}_{D}}$ -configurations, where $D\,=\,\left\{ {{d}_{1}},\ldots ,{{d}_{r}} \right\}$ (a set of $r$ positive integers with repetition allowed) is the type of a given complete intersection in ${{\mathbb{P}}^{n}}$ . We show that the Hilbert function of any ${{k}_{D}}$ -configuration can be obtained from those of smaller ${{k}_{D}}$ -configurations. We then provide applications of this result in two different directions, both of which are motivated by corresponding results about $k$ -configurations.

Détail

DOI : 10.4153/CJM-2005-017-2

Mots-clés : 13D40, 14M10

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