The maximal unipotent finite quotient, unusual torsion in Fano threefolds, and exceptional Enriques surfaces
Andrea Fanelli,
Stefan Schröer
Abstract:We introduce and study the maximal unipotent finite quotient for algebraic group schemes in positive characteristics. Applied to Picard schemes, this quotient encodes exotic torsion. We construct integral Fano threefolds where such exotic torsion actually appears. The existence of such threefolds is surprising, because the exotic torsion vanishes for del Pezzo surfaces. Our construction relies on the theory of exceptional Enriques surfaces, as developed by Ekedahl and Shepherd-Barron.
Set email alert for when this publication receives citations?
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.