3 papers
math.AG2005
Geometry over composition algebras : projective geometry
Pierre-Emmanuel Chaput
The purpose of this article is to introduce projective geometry over composition algebras : the equivalent of projective spaces and Grassmannians over them are defined. It will fol…
math.AG2002
Severi, Scorza varieties and Jordan algebras
P. E. Chaput
The Severi and Scorza varieties are the limiting cases of a theorem of Zak conjectured by Hartshorne. Zak also classified the Severi and Scorza varieties. Surprisingly enough, ther…
math.AG2001
Severi varieties
P. E. Chaput
R. Hartshorne conjectured and F. Zak proved that any n-dimensional smooth non-degenerate complex algebraic variety X in a m-dimensional projective space P satisfies Sec(X)=P if m<3…