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arXiv · alg-geom/9505019

Mapping threefolds onto three-quadrics

Carmen Schuhmann
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Abstract

We prove that the degree of a nonconstant morphism from a smooth projective 3-fold $X$ with Néron-Severi group ${\bf Z}$ to a smooth 3-dimensional quadric is bounded in terms of numerical invariants of $X$. In the special case where $X$ is a 3-dimensional cubic we show that there are no such morphisms. The main tool in the proof is Miyaoka's bound on the number of double points of a surface.

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Carmen Schuhmann. 1995-05-19. Mapping threefolds onto three-quadrics. https://arxiv.org/abs/alg-geom/9505019

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