On Zariski's theorem in positive characteristic
Journal of the European Mathematical Society, Tome 15 (2013) no. 5, pp. 1783-1803
Voir la notice de l'article provenant de la source EMS Press
In the current paper we show that the dimension of a family V of irreducible reduced curves in a given ample linear system on a toric surface S over an algebraically closed field is bounded from above by −KS.C+pg(C)−1, where C denotes a general curve in the family. This result generalizes a famous theorem of Zariski to the case of positive characteristic. We also explore new phenomena that occur in positive characteristic: We show that the equality dim(V)=−KS.C+pg(C)−1 does not imply the nodality of C even if C belongs to the smooth locus of S, and construct reducible Severi varieties on weighted projective planes in positive characteristic, parameterizing irreducible reduced curves of given geometric genus in a given very ample linear system.
Classification :
14-XX, 00-XX
Keywords: Curves on algebraic surfaces, Severi varieties
Keywords: Curves on algebraic surfaces, Severi varieties
@article{JEMS_2013_15_5_a5,
author = {Ilya Tyomkin},
title = {On {Zariski's} theorem in positive characteristic},
journal = {Journal of the European Mathematical Society},
pages = {1783--1803},
publisher = {mathdoc},
volume = {15},
number = {5},
year = {2013},
doi = {10.4171/jems/403},
url = {http://geodesic.mathdoc.fr/articles/10.4171/jems/403/}
}
Ilya Tyomkin. On Zariski's theorem in positive characteristic. Journal of the European Mathematical Society, Tome 15 (2013) no. 5, pp. 1783-1803. doi: 10.4171/jems/403
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