Geometric properties of the double-point divisor

Author:
Bo Ilic

Journal:
Trans. Amer. Math. Soc. **350** (1998), 1643-1661

MSC (1991):
Primary 14N05, 14C20, 14J40

DOI:
https://doi.org/10.1090/S0002-9947-98-01928-X

MathSciNet review:
1422899

Full-text PDF Free Access

Abstract | References | Similar Articles | Additional Information

Abstract: The locus of double points obtained by projecting a variety $X^{n} \subset \mathbf {P}^N$ to a hypersurface in $\mathbf {P}^{n+1}$ moves in a linear system which is shown to be ample if and only if $X$ is not an isomorphic projection of a Roth variety. Such Roth varieties are shown to exist, and some of their geometric properties are determined.

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Additional Information

**Bo Ilic**

Affiliation:
Department of Mathematics, Columbia University, New York, New York 10027

Address at time of publication:
Department of Mathematics, University of California, Los Angeles, California 90024

Email:
ilic@math.ucla.edu

Keywords:
Double-point divisor,
Roth variety,
Castelnuovo variety,
secant variety,
conductor,
projection

Received by editor(s):
July 20, 1996

Article copyright:
© Copyright 1998
American Mathematical Society