Publication:
Focal loci in G(1,N)

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http://intlpress.com/AJM/p/2005/9_4/AJM-9-4-449-472.pdf
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2005-12
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Bertolini, Marina
Turrini, Cristina
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International Press
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Abstract
We introduce the different focal loci (focal points, planes and hyperplanes) of (n - 1)-dimensional families (congruences) of lines in P-n and study their invariants, geometry and the relation among them. We also study some particular congruences whose focal loci have special behaviour, namely (n - 1)-secant lines to an (n - 2)-fold and (n - 1)-tangent lines to a hypersurface. In case n = 4 we also give, under some smoothness assumptions, a classification result for these congruences.
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Geometria algebraica
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1201.01 Geometría Algebraica
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https://hdl.handle.net/20.500.14352/49831
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