Special SFBseminar day  Supersingular K3 surfaces are unirational
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SFBSeminar
Christian Liedtke (München)
What 


When 
Dec 19, 2013 from 04:45 pm to 05:45 pm 
Where  Essen, WSCNU3.05 
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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.