%0 Journal Article
%A Arrondo Esteban, Enrique
%A Bertolini, Marina
%A Turrini, Cristina
%T Focal loci in G(1,N)
%D 2005
%@ 1093-6106
%U https://hdl.handle.net/20.500.14352/49831
%X 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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