Tue, 01 Mar 2016
14:30
L3

Kerdock matrices and the efficient quantization of subsampled measurements

Andrew Thompson
(University of Oxford)
Abstract

Kerdock matrices are an attractive choice as deterministic measurement matrices for compressive sensing. I'll explain how Kerdock matrices are constructed, and then show how they can be adapted to one particular  strategy for quantizing measurements, in which measurements exceeding the desired dynamic range are rejected.

Wed, 17 Feb 2016

11:00 - 11:30
N3.12

The Riemann zeta function, quantum chaos and random matrices

Simon Myerson
(Oxford)
Abstract
The Riemann zeta function is linked to quantum chaology by some totally neat results and utterly wacky conjectures concerning random matrices. Join me to see the horrifying extent of these unexpected connections!
Wed, 24 Feb 2016

11:00 - 12:30
N3.12

Outer Automorphisms of Hyperbolic Groups

Alex Margolis
(Oxford)
Abstract

I will talk about a remarkable theorem by Paulin, which says
that if a one-ended hyperbolic group has infinite outer automorphism
group, then it splits over a two-ended subgroup. In particular, this
gives a condition which ensures a hyperbolic group doesn't have property
(T).

 

Tue, 23 Feb 2016

15:00 - 16:00
C4

Galois Characterization of Henselian Fields

Chenkai Wang
(Oxford University)
Abstract

 I will talk about Jochen’s theorem about the existence of some non-trivial Henselian valuation given by investigating the absolute Galois group.

Mon, 29 Feb 2016
16:30
C1

Torelli and Borel-Tits theorems via trichotomy

Carlos Alfonso Ruiz Guido
((Oxford University))
Abstract

Using the "trichotomy principle" by Boris Zilber I will give model theoretic proofs of appropriate versions of Torelli theorem and Borel-Tits theorem. The first one has interesting applications to anabelian geometry, I won't assume any prior knowledge in model theory.

Many of us know the feeling of standing in front of a subway map in a strange city, baffled by the multi-coloured web staring back at us and seemingly unable to plot a route from point A to point B. Now, a team of physicists and mathematicians has attempted to quantify this confusion and find out whether there is a point at which navigating a route through a complex urban transport system exceeds our cognitive limits.

Tue, 26 Apr 2016

12:00 - 13:15
L4

Extended QFT in Euclidean and Minkowskian signatures

Andre Henriques
Abstract

I'll explain the formalism of extended QFT, while
focusing on the cases of two dimensional conformal field theories,
and three dimensional topological field theories.

Wed, 01 Jun 2016
15:00
L4

Computing Factor Tables, and Tables of Class Numbers

Roger Heath-Brown
(University of Oxford)
Abstract

Efficient factorization or efficient computation of class 
numbers would both suffice to break RSA.  However the talk lies more in 
computational number theory rather than in cryptography proper. We will 
address two questions: (1) How quickly can one construct a factor table 
for the numbers up to x?, and (2) How quickly can one do the same for the 
class numbers (of imaginary quadratic fields)? Somewhat surprisingly, the 
approach we describe for the second problem is motivated by the classical 
Hardy-Littlewood method.

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