Thu, 28 May 2015

16:00 - 17:00
C2

Hyperbolic volume of links, via pants graph and train tracks

Antonio De Capua
(Oxford)
Abstract

A result of Jeffrey Brock states that, given a hyperbolic 3-manifold which is a mapping torus over a surface $S$, its volume can be expressed in terms of the distance induced by the monodromy map in the pants graph of $S$. This is an abstract graph whose vertices are pants decompositions of $S$, and edges correspond to some 'elementary alterations' of those.
I will show how this theorem gives an estimate for the volume of hyperbolic complements of closed braids in the solid torus, in terms of braid properties. The core piece of such estimate is a generalization of a result of Masur, Mosher and Schleimer that train track splitting sequences (which I will define in the talk) induce quasi-geodesics in the marking graph.

Thu, 21 May 2015

16:00 - 17:00
C2

Ricci flow invariant curvature conditions

Matthias Wink
(Oxford)
Abstract

In this talk we're going to discuss Hamilton's maximum principle for the Ricci flow. As an application, I would like to explain a technique due to Boehm and Wilking which provides a general tool to obtain new Ricci flow invariant curvature conditions from given ones. As we'll see, it plays a key role in Brendle and Schoen's proof of the differentiable sphere theorem.

Thu, 14 May 2015

16:00 - 17:00
C2

Zariski Geometries

Carlos Alfonso Ruiz
(Oxford)
Abstract
I will present a model theoretic point of view of algebraic geometry based on certain objects called Zariski Geometries. They were introduced by E. Hrushovski and B. Zilber and include classical objects like compact complex manifolds, algebraic varieties and rigid analytic varieties. Some connections with non commutative geometry have been found by B. Zilber too. I will concentrate on the relation between Zariski Geometries and schemes. 
Thu, 07 May 2015

16:00 - 17:00
C2

The geometry of the Ising model

Bruce Bartlett
(Oxford)
Abstract

The Ising model is a well-known statistical physics model, defined on a two-dimensional lattice. It is interesting because it exhibits a "phase transition" at a certain critical temperature. Recent mathematical research has revealed an intriguing geometry in the model, involving discrete holomorphic functions, spinors, spin structures, and the Dirac equation. I will try to outline some of these ideas.

Mon, 15 Jun 2015

16:00 - 17:00
C2

Almost similar p-adic representations: crystalline versus étale.

Junghwan Lim
(Oxford)
Abstract

I will introduce the general idea of p-adic Hodge theory from the view point of a beginner. Also, I will give a sketch of the proof of the crystalline comparison theorem in the case of good reduction using 'almost mathematics'.

 

Mon, 01 Jun 2015

16:00 - 17:00
C2

Perfectoid spaces and the tilting equivalence

Alex Betts
(Oxford)
Abstract

We will give a sketch overview of Scholze's theory of perfectoid spaces and the tilting equivalence, starting from Huber's geometric approach to valuation theory. Applications to weight-monodromy and p-adic Hodge theory we will only hint at, preferring instead to focus on examples which illustrate the philosophy of tilting equivalence.
 

Mon, 27 Apr 2015

16:00 - 17:00
C2

Langlands Functoriality for Symplectic Groups

Benjamin Green
(Oxford)
Abstract

In this talk I will describe two instances of Langlands functoriality concerning the group $\mathrm{Sp}_{2n}$. I will then very briefly explain how this enables one to attach Galois representations to automorphic representations of (inner forms of) $\mathrm{Sp}_{2n}$. 

Tue, 09 Jun 2015

17:00 - 18:00
C2

TBA

Benjamin Klopsch
(Duesseldorf)
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