2002/07/12 by Pietro De Poi · 1 citation
Mathematics · #Algebra over a field #Algebraic Geometry and Number Theory #Algebraic curve #Algebraic number #Art #Codimension #Combinatorics #Congruence (geometry) #Finite Group Theory Research #Fyodor #Geometry #Humanities #Literature #Mathematical analysis #Mathematics #Order (exchange) #Philosophy #Point (geometry) #Pure mathematics #Tensor decomposition and applications #math.AG #msc:14J30 #msc:14M15 #msc:14N05 #msc:51N35
paper · pdf · doi:10.1081/agb-120018514
AMS-LaTeX2e, 14 pages
arxiv created 2002/07/12 · openalex publication_date 2003/01/05 · openalex created_date 2016/06/24 · arxiv updated 2017/02/03 · openalex updated_date 2026/08/05
In this article we classify all the smooth threefolds in ℙ5 with an apparent quadruple point provided that the family of its 4-secant lines is an irreducible (first order) congruence. This is sufficient to conclude the classification of all the smooth codimension two varieties in ℙ n with one apparent (n − 1)-point and with irreducible family of (n − 1)-secant lines.