A note on quasi-Hermitian varieties and singular quasi-quadrics
De Winter, S. ; Schillewaert, J.
Bull. Belg. Math. Soc. Simon Stevin, Tome 17 (2010) no. 1, p. 911-918 / Harvested from Project Euclid
{\em Quasi-quadrics} were introduced by Penttila, De Clerck, O'Keefe and Hamilton in [2]. They are defined as point sets which have the same intersection numbers with respect to hyperplanes as non-singular quadrics. We extend this definition in two ways. The first extension is to {\em quasi-Hermitian varieties}, which are point sets which have the same intersection numbers with respect to hyperplanes as non-singular Hermitian varieties. The second one is to {\em singular quasi-quadrics}, i.e. point sets $\mathcal{K}$ which have the same intersection numbers with respect to hyperplanes as singular quadrics. Our starting point was to investigate whether every singular quasi-quadric is a cone over a non-singular quasi-quadric. This question is tackled in the case of a point set $\mathcal{K}$ with the same intersection numbers with respect to hyperplanes as a point over an ovoid.
Publié le : 2010-12-15
Classification: 
@article{1292334065,
     author = {De Winter, S. and Schillewaert, J.},
     title = {A note on quasi-Hermitian varieties and singular quasi-quadrics},
     journal = {Bull. Belg. Math. Soc. Simon Stevin},
     volume = {17},
     number = {1},
     year = {2010},
     pages = { 911-918},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1292334065}
}
De Winter, S.; Schillewaert, J. A note on quasi-Hermitian varieties and singular quasi-quadrics. Bull. Belg. Math. Soc. Simon Stevin, Tome 17 (2010) no. 1, pp.  911-918. http://gdmltest.u-ga.fr/item/1292334065/