Thu, 17 Nov 2016
11:00
C5

O-minimality and the Zilber-Pink conjecture for (pure) Shimura varieties

Chris Daw
(Oxford)
Abstract


In this talk, we will explain how the counting theorems of Pila and Wilkie lead to a conditional proof of the aforementioned conjecture. In particular, we will explain how to generalise the work of Habegger and Pila on a product of modular curves. 
Habegger and Pila were able to prove that the Zilber-Pink conjecture holds in such a product if the so-called weak complex Ax and large Galois orbits conjectures are true. In fact, around the same time, Pila and Tsimerman proved a stronger statement than the weak complex Ax conjecture, namely, the Ax-Schanuel conjecture for the $j$-function. We will formulate Ax-Schanuel and large Galois orbits conjectures for general Shimura varieties and attempt to imitate the Habegger-Pila strategy. However, we will encounter an additional difficulty in bounding the height of a pre-special subvariety.

This is joint work with Jinbo Ren.
 

Tue, 15 Nov 2016
13:00
C4

Introduction

Barbara Mahler, Nina Otter and Bernadette Stolz.
Abstract

 In the first meeting of the seminar we, and all participants who wish to do so, will each briefly introduce ourselves and our research interests. We will decide future talks and papers to read during this meeting.

Tue, 09 May 2017

17:00 - 18:15
L1

The Butterfly Effect: What Does It Really Signify? - Tim Palmer

Tim Palmer
(University of Oxford)
Abstract

Meteorologist Ed Lorenz was one of the founding fathers of chaos theory. In 1963, he showed with just three simple equations that the world around us could be both completely deterministic and yet practically unpredictable. More than this, Lorenz discovered that this behaviour arose from a beautiful fractal geometric structure residing in the so-called state space of these equations. In the 1990s, Lorenz’s work was popularised by science writer James Gleick. In his book Gleick used the phrase “The Butterfly Effect” to describe the unpredictability of Lorenz’s equations. The notion that the flap of a butterfly’s wings could change the course of future weather was an idea that Lorenz himself used in his outreach talks.

However, Lorenz used it to describe something much more radical than can be found in his three simple equations. Lorenz didn’t know whether the Butterfly Effect, as he understood it, was true or not. In fact, it lies at the heart of one of the Clay Mathematics Millennium Prize problems, and is still an open problem today. In this talk I will discuss Lorenz the man, his background and his work in the 1950s and 1960s, and will compare and contrast the meaning of the “Butterfly Effect" as most people understand it today, and as Lorenz himself intended it to mean. The implications of the “Real Butterfly Effect" for understanding the predictability of nonlinear multi-scale systems (such as weather and climate) will be discussed. No technical knowledge of the field is assumed. 

Please email @email to register

Further reading:
T.N.Palmer, A. Döring and G. Seregin (2014): The Real Butterfly Effect. Nonlinearity, 27, R123-R141.

The University of Oxford’s Ashmolean Museum is not only an exhibitor of art, but home to vital artistic research. The museum’s collections are investigated by some of the world’s leading historians, archaeologists, anthropologists and… mathematicians?

Throughout November 2016, the Ashmolean Museum and Oxford Mathematics proudly present Random Walks, a series of short films that present the historical world through mathematical eyes.

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