University of Maryland
Algebra-Number Theory Seminar Abstracts
(May 25) Tonghai Yang:
Existence of algebraic Hecke characters -
In this talk, we will explain that a weak version
of the Brumer-Stark conjecture is equivalent to the existence
of certain algebraic Hecke characters, which can be viewed as
generalization of the Weil's Jacobi characters. As a consequence,
we show that the Brumer-Stark conjecture in CM cases implies the
Brumer-Stark conjecture in general. (May 25) Douglas Ulmer:
On the maximum rank of an elliptic curve
as a function of its conductor -
It is widely believed that there are elliptic curves over Q with
Mordell-Weil group of arbitrarily large rank. We prove an analogous
statement for elliptic curves over function fields of curves over
finite fields. In contrast to an earlier example of Shafarevitch and
Tate, our curves are "non-isotrivial," i.e., they have non-constant
j-invariant. We also discuss bounds suggested by our example for the
rank of an elliptic curve in terms of its conductor.
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