Umberto Zannier (Scuola Normale Superiore)

Abelian varieties not isogenous to any Jacobian.

ABSTRACT: It is well known that in dimension g\ge 4
there exist  complex abelian varieties not isogenous to
  any Jacobian. A question of Katz and Oort asked whether
  one can find such examples over the field of algebraic numbers.
 This was answered affirmatively by Oort-Chai under the
  Andre'-Oort conjecture, and by Tsimerman unconditionally.
  They gave examples within Complex Multiplication.
   In joint work with Masser, by means of a completely
  different method, we proved that in a sense the "general
 abelian variety over \overline\Q is indeed not isogenous
 to any Jacobian. I shall illustrate the context and the
basic principles
  of the proofs.

Recording: https://us02web.zoom.us/rec/share/fY7RBx4iwiKg5_u8ezJesTGlthUhYvaBxbzlsfFY_-nTXedV9iFhgELjoXa7PRDg.DpCqV--62c6EjEB1

The meeting will be open from 14.15 (local time) for a virtual coffee with the speaker. 

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