Seminar series
Date
Thu, 03 Feb 2011
Time
16:00 -
17:00
Location
L3
Speaker
Jacob Tsimerman
Organisation
Princeton University
We discuss the following question of Nick Katz and Frans Oort: Given an
Algebraically closed field K , is there an Abelian variety over K of
dimension g which is not isogenous to a Jacobian? For K the complex
numbers
its easy to see that the answer is yes for g>3 using measure theory, but
over a countable field like $\overline{\mbthbb{Q}}$ new methods are required. Building on
work
of Chai-Oort, we show that, as expected, such Abelian varieties exist for
$K=\overline{\mbthbb{Q}}$ and g>3 . We will explain the proof as well as its connection to
the
Andre Oort conjecture.