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On projective varieties of dimension n+k covered by k-spaces

Emilia Mezzetti·Orsola Tommasi
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Abstract

We study families of linear spaces in projective space whose union is a proper subvariety X of the expected dimension. We establish relations between configurations of focal points and existence or non-existence of a fixed tangent space to X along a general element of the family. We apply our results to the classification of ruled 3-dimensional varieties.

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Emilia Mezzetti, Orsola Tommasi. 2001-11-30. On projective varieties of dimension n+k covered by k-spaces. https://arxiv.org/abs/math/0111319

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