Mumford curves parameterizing hyperelliptic curves

Speaker: 

Samuel Kadziela

Institution: 

University of Illinois at Urbana-Champaign

Time: 

Tuesday, June 5, 2007 - 2:00pm

Location: 

MSTB 254

Tate's work on Rigid Analytic Spaces can be used to obtain the
$p$-adic uniformization of a curve. In this talk, I will describe a
criterion determining which hyperelliptic curves admit this type of
uniformization. Then, we will discuss Mumford curves, which are the
uniformizing spaces, and explain how to approximate the $p$-adic
uniformization of a given totally split hyperelliptic curve.

Attacking the ABC Conjecture with elliptic curves

Speaker: 

Lily Khadjavi

Institution: 

Loyola Marymount University

Time: 

Tuesday, May 1, 2007 - 2:00pm

Location: 

MSTB 254

This talk will investigate the ABC Conjecture, an open problem with a surprising number of implications, viewed by some as a "holy grail" of number theory. We'll describe the conjecture and then consider an idea of Noam Elkies' which exploits special maps from curves to the projective line. Exploiting the group structure of elliptic curves along with these maps, we make progress towards a weak ABC Conjecture. This is joint work with Victor Scharaschkin.

ell-torsion of Abelian Varieties

Speaker: 

Chris Hall

Institution: 

University of Texas

Time: 

Tuesday, April 24, 2007 - 2:00pm

Location: 

MSTB 254

Let $K$ be a number field and $E/K$ an elliptic curve without
complex multiplication. A well-known theorem of Serre asserts that the
Galois group of $K(E[\ell])/K$ is as all of ${\rm GL}_2(\Z/\ell)$ for any
sufficiently large prime $\ell$. If we replace $E/K$ by a polarized abelian
variety $A/K$ with trivial endomorphism ring, then Serre later showed
that the Galois group of $K(A[\ell])/K$ is also as large as possible, for
all sufficiently large $\ell$, provided $\dim(A)$ is 2,6 or odd. We will
show how to prove a similar result for `most' $A$ and without any
restriction on $\dim(A)$.

Low Correlation Zone Signal Sets

Speaker: 

Professor Guang Gong

Institution: 

USC and Univ. of Waterloo

Time: 

Thursday, March 1, 2007 - 12:00pm

Location: 

MSTB 254

Abstract:

In this talk, I will present a connection between designing low
correlation zone (LCZ) sequences and the results of correlation
of sequences with subfield decompositions. This results
in low correlation zone signal sets with huge sizes over three
different alphabetic sets: finite field of size $q$, integer
residue ring modulo $q$, and the subset in the complex field which
consists of powers of a primitive $q$-th root of unity. A connection between these
constructions and ``completely
non-cyclic'' Hadamard matrices will be shown. I will also provide some open problems
along this direction.

Joint work with Solomon W. Golomb and Hongyeop Song.

Dedekind Zeta functions at s=-1 and the Fitting ideal of the tame kernel in a relative quadratic extension

Speaker: 

Jonathan Sands

Institution: 

Univ. of Vermont and UCSD

Time: 

Tuesday, February 13, 2007 - 12:00pm

Location: 

MSTB 254

Brumer's conjecture states that Stickelberger elements combining values of L-functions at s=0 for an abelian extension of number fields E/F should annihilate the ideal class group of E when it is considered as module over the appropriate group ring. In some cases, an ideal obtained from these Stickelberger elements has been shown to equal a Fitting ideal connected with the ideal class group. We consider the analog of this at s=-1, in which the class group is replaced by the tame kernel, which we will define. For a field extension of degree 2, we show that there is an exact equality etween the Fitting ideal of the tame kernel and the most natural higher Stickelberger ideal; the 2-part of this equality is conditional on the Birch-Tate conjecture.

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