Mon, 20 Feb 2017

15:45 - 16:45
L3

Bloch functions, asymptotic variance, and geometric zero packing

HAKAN HEDENMALM
(KTH Stockholm)
Abstract

Motivated by a problem in quasiconformal mapping, we introduce a new type of problem in complex analysis, with its roots in the mathematical physics of the Bose-Einstein condensates in superconductivity.The problem will be referred to as \emph{geometric zero packing}, and is somewhat analogous to studying Fekete point configurations.The associated quantity is a density, denoted  $\rho_\C$ in the planar case, and $\rho_{\mathbb{H}}$ in the case of the hyperbolic plane.We refer to these densities as \emph{discrepancy densities for planar and hyperbolic zero packing}, respectively, as they measure the impossibility of atomizing the uniform planar and hyperbolic area measures.The universal asymptoticvariance $\Sigma^2$ associated with the boundary behavior of conformal mappings with quasiconformal extensions of small dilatation is related to one of these discrepancy densities: $\Sigma^2= 1-\rho_{\mathbb{H}}$.We obtain the estimates$2.3\times 10^{-8}<\rho_{\mathbb{H}}\le0.12087$, where the upper estimate is derived from the estimate from below on $\Sigma^2$ obtained by Astala, Ivrii, Per\"al\"a,  and Prause, and the estimate from below is much more delicate.In particular, it follows that $\Sigma^2<1$, which in combination with the work of Ivrii shows that the maximal fractal dimension of quasicircles conjectured by Astala cannot be reached.Moreover, along the way, since the universal quasiconformal integral means spectrum has the asymptotics$\mathrm{B}(k,t)\sim\frac14\Sigma^2 k^2|t|^2$ for small $t$ and $k$, the conjectured formula $\mathrm{B}(k,t)=\frac14k^2|t|^2$ is not true.As for the actual numerical values of the discrepancy density $\rho_\C$, we obtain the estimate from above $\rho_\C\le0.061203\ldots$ by using the equilateral triangular planar zero packing, where the assertion that equality should hold can be attributed to Abrikosov. The values of $\rho_{\mathbb{H}}$ is expected to be somewhat close to the value of $\rho_\C$.

Wed, 15 Feb 2017

11:00 - 12:00
N3.12

An approach to Quantum Gravity

Renee Hoekzema
(University of Oxford)
Abstract

I'll be talking about my masters' research in Quantum Gravity in a way that is accessible to mathematicians.

Wed, 08 Feb 2017

11:00 - 12:00
N3.12

TBC

Thomas Wasserman
(University of Oxford)
Wed, 25 Jan 2017

11:00 - 12:00
N3.12

TBC

Craig Smith
(University of Oxford)
Tue, 07 Feb 2017
14:30
L6

Designs Beyond Quasirandomness

Stefan Glock
(Birmingham University)
Abstract

In a recent breakthrough, Peter Keevash proved the Existence conjecture for combinatorial designs, which has its roots in the 19th century. In joint work with Daniela Kühn, Allan Lo and Deryk Osthus, we gave a new proof of this result, based on the method of iterative absorption. In fact, `regularity boosting’ allows us to extend our main decomposition result beyond the quasirandom setting and thus to generalise the results of Keevash. In particular, we obtain a resilience version and a minimum degree version. In this talk, we will present our new results within a brief outline of the history of the Existence conjecture and provide an overview of the proof.

Thu, 19 Jan 2017
11:00
C5

Towards a Ladder Theorem for Specialisations

Ugur Efem
Abstract


In this talk I will present some answers to the question when every specialisation from a \kappa-saturated extension of 
a Zariski structure is \kappa-universal? I will show that for algebraically closed fields, all specialisations from a \kappa-
saturated extension is \kappa-universal. More importantly, I will consider this question for finite and infinite covers of
Zariski structures. In these cases I will present a counterexample to show that there are covers of Zariski structures 
which have specialisations from a \kappa-saturated extension that are not \kappa-universal. I will present some natural 
conditions on the fibres under which all specialisations from a \kappa-saturated extension of a cover is \kappa-universal. 
I will explain how this work points towards a prospective Ladder Theorem for Specialisations and explain difficulties and 
further works that needs to be considered.
 

Fri, 17 Feb 2017

17:00 - 18:00
L2

InFoMM The Reddick Lecture

Tom Hebbert
(Supply Chain Director at Tesco PLC)
Abstract

Data science: The secret to unlocking operational performance within the UK’s largest retail supply chain

 

Chris Reddick was instrumental in setting up the InFoMM CDT. After helping secure the EPSRC funding he chaired the Industrial Engagement Committee and supported the CDT in all its Industrial relations. The success of the CDT, as evidenced by the current size of the industrial partnership and the vibrant programme we have developed, is in no small part due to Chris' charm, vision, and tenacity.

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