IJPAM: Volume 57, No. 4 (2009)

POSTULATION OF GENERAL UNIONS OF
LINES AND A FEW PLANES IN $\mathbb {P}^4$

E. Ballico
Department of Mathematics
University of Trento
38 123 Povo (Trento) - Via Sommarive, 14, ITALY
e-mail: ballico@science.unitn.it


Abstract.Let $X \subset \mathbb {P}^4$ be a general union of $x$ planes and $y$ lines. Let $k\ge 1$ be the minimal integer such that $x\binom{k+2}{2} -x(x-1)/2 + y(k+1) \le \binom{k+4}{4}$. Assume $x \le k-1$. Then $X$ has the expected postulation.

Received: October 28, 2009

AMS Subject Classification: 14N05

Key Words and Phrases: postulation, unions of planes, planes in $\mathbb {P}^4$

Source: International Journal of Pure and Applied Mathematics
ISSN: 1311-8080
Year: 2009
Volume: 57
Issue: 4