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SUMMARY:Prym varieties of triple coverings - Ortega\, A (Humboldt)
DTSTART:20110324T140000Z
DTEND:20110324T150000Z
UID:TALK30381@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:Classical Prym varieties are principally polarised abelian var
 ieties associated to etale double coverings between curves. We study a spe
 cial class of Prym-Tjurin varieties of exponent 3\, coming from non-cyclic
 etale triple coverings of curves of genus 2. We show that the moduli space
  of such coverings is a rational threefold\, mapping 10:1 via the Prym map
  to the moduli space of principal polarised abelian surfaces. The crucial 
 ingredient used to obtain such an explicit description of the moduli space
 \, is that any genus 4 curve which admits a non-cyclic triple cover over a
  genus 2 curve\, is actually hyperelliptic. We also describe the extended 
 Prym map from the moduli space of *admissible* S_3-covers onto A_2 . This 
 is a joint work with Herbert Lange\n\n
LOCATION:Seminar Room 2\, Newton Institute Gatehouse
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