Tue, 26 Jan 2016

12:00 - 13:15
L4

Elliptic polylogarithms and string amplitudes

Dr Erik Panzer
(Oxford)
Abstract
Recent results showed that the low energy expansion of closed superstring amplitudes can be expressed in terms of

single-valued multiple elliptic polylogarithms. I will explain how these functions may be defined as iterated integrals on the torus and

sketch how they arise from Feynman integrals.
Wed, 20 Jan 2016

11:00 - 12:30
S2.37

Bieberbach's Theorems

Robert Kropholler
(Oxford)
Abstract
I will go through a proof of Bieberbach's theorems proving that a group acting cocompactly on Euclidean n-space has a subgroup consisting of n independent translations. Time permitting I will also prove that there is a bound on the number of such groups for each dimension n. I will assume very little requiring only a small amount of group theory and linear algebra for the proofs. 
Mon, 18 Jan 2016

12:00 - 13:00
L5

Modular Forms from the Arithmetic of Singular Calabi-Yau Manifolds

Philip Candelas
(Oxford)
Abstract

I will give an introductory account of the zeta-functions for one-parameter families of CY manifolds. The aim of the talk is to point out that the zeta-functions corresponding to singular manifolds of the family correspond to modular forms. In order to give this introductory account I will give a lightning review of finite fields and of the p-adic numbers.

 
 
Thu, 18 Feb 2016

14:00 - 15:00
L5

Ten things you should know about quadrature

Professor Nick Trefethen
(Oxford)
Abstract

Quadrature is the term for the numerical evaluation of integrals.  It's a beautiful subject because it's so accessible, yet full of conceptual surprises and challenges.  This talk will review ten of these, with plenty of history and numerical demonstrations.  Some are old if not well known, some are new, and two are subjects of my current research.

Tue, 19 Jan 2016

15:45 - 16:45
L4

Symplectic categories in Derived Geometry

Lino Amorim
(Oxford)
Abstract

I will describe a construction of the Weinstein symplectic category of Lagrangian correspondences in the context of shifted symplectic geometry. I will then explain how one can linearize this category starting from a "quantization" of  (-1)-shifted symplectic derived stacks: we assign a perverse sheaf to each (-1)-shifted symplectic derived stack (already done by Joyce and his collaborators) and a map of perverse sheaves to each (-1)-shifted Lagrangian correspondence (still conjectural).

Mon, 01 Feb 2016
02:15
L4

Torelli theorems and integrable systems for parabolic Higgs bundles

Marina Logares
(Oxford)
Abstract

In the same way that the classical Torelli theorem determines a curve from its polarized Jacobian we show that moduli spaces of parabolic bundles and parabolic Higgs bundles over a compact Riemann surface X  also determine X. We make use of a theorem of Hurtubise on the geometry of algebraic completely integrable systems in the course of the proof. This is a joint work with I. Biswas and T. Gómez 

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