Buondì,
siete invitati mercoledì prossimo 9 ottobre ad un seminario di
geometria algebrica, seguono i dettagli.
Bruno
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Mercoledi 9 ottobre ore 14:30 (Sala Seminari)
Christian Liedtke
Univ. München (Germany)
terra' il seguente seminario
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Title:
Supersingular K3 Surfaces are Unirational
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Abstract:
We show that supersingular K3 surfaces are related by purely
inseparable isogenies. As an application, we deduce that they are
unirational, which confirms conjectures of Artin, Rudakov,
Shafarevich, and Shioda.
The main ingredient in the proof is to use the formal Brauer group of
a Jacobian elliptically fibered supersingular K3 surface to construct
a family of "moving torsors" under this fibration that eventually
relates supersingular
K3 surfaces of different Artin invariants by purely inseparable
isogenies. If time permits, we will show how these "moving torsors"
exhibit the moduli space of rigidified supersingular K3 crystals as an
iterated projective
bundle over a finite field.
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