Thu, 27 Apr 2017
11:00
C5

On cohomology of function fields

Adam Topaz
(Oxford)
Abstract


 This talk will discuss the so-called ``generic cohomology’’ of function fields over algebraically closed fields, from the point of view of motives and/or Zariski geometry. In particular, I will describe some interesting connections between cup products, algebraic dependence, and (geometric) valuation theory. As an application, I will mention a new result which reconstructs higher-dimensional function fields from their generic cohomology, endowed with some additional motivic data. 

   Everyone welcome!
 

Wed, 03 May 2017
16:00
C2

Ultra-arcs

Paul Bankston
(Milwaukee and Aberystywyth)
Fri, 26 May 2017

11:45 - 12:45
L4

InFoMM CDT Group Meeting

Davin Lunz, Bogdan Toader, Jessica Williams
(Mathematical Institute)
Tue, 25 Apr 2017
14:30
L3

Reed's Conjecture and Strong Edge Coloring

Marthe Bonamy
(Bordeaux)
Abstract

The chromatic number of a graph is trivially bounded from above by the maximum degree plus one, and from below by the size of a largest clique. Reed proved in 1998 that compared to the trivial upper bound, we can always save a number of colors proportional to the gap between the maximum degree and the size of a largest clique. A key step in the proof deals with how to spare colors in a graph whose every vertex "sees few edges" in its neighborhood. We improve the existing approach, and discuss its applications to Reed's theorem and strong edge coloring.  This is joint work with Thomas Perrett (Technical University of Denmark) and Luke Postle (University of Waterloo).

Tue, 23 May 2017

15:45 - 16:45
L4

On Short Time Existence of Lagrangian Mean Curvature Flow

Tom Begley
(Cambridge)
Abstract

The goal of this talk will be to give an overview of recent work, joint with Kim Moore, on a short time existence problem in Lagrangian mean curvature flow. More specifically, we consider a compact initial Lagrangian submanifold with a finite number of singularities, each asymptotic to a pair of transversely intersecting planes. We show it is possible to construct a smooth Lagrangian mean curvature flow, existing for positive times, that attains the singular Lagrangian as its initial condition in a suitable weak sense.  The construction uses a family of smooth solutions whose initial conditions approximate the singular Lagrangian. In order to appeal to compactness theorems and produce the desired solution, it is necessary to first establish uniform curvature estimates on the approximating family. As time allows I hope to focus in particular on the proof of these estimates, and their role in the proof of the main theorem.

Tue, 09 May 2017

15:45 - 16:45
L4

Limits of Yang-Mills alpha-connections

Casey Lynn Kelleher
(UC Irvine)
Abstract
In the spirit of recent work of Lamm, Malchiodi and Micallef in the setting of harmonic maps, we identify Yang-Mills connections obtained by approximations with respect to the Yang-Mills alpha-energy. More specifically, we show that for the SU(2) Hopf fibration over the four sphere, for sufficiently small alpha values the rotation invariant ADHM connection is the unique alpha-critical point which has Yang-Mills alpha-energy lower than a specific threshold.
Tue, 02 May 2017

15:45 - 16:45
L4

Gopakumar-Vafa type invariants for Calabi-Yau 4-folds

Yalong Cao
(Oxford)
Abstract
As an analogy of Gopakumar-Vafa conjecture for CY 3-folds, Klemm-Pandharipande proposed GV type invariants on CY 4-folds using GW theory and conjectured their integrality. In this talk, we propose a sheaf theoretical interpretation to these invariants using Donaldson-Thomas theory on CY 4-folds. This is a joint work with Davesh Maulik and Yukinobu Toda.

The Andrew Wiles Building, our home here in Oxford, is very much a public space with its large exhibition and conference facilities and public cafe. We have hosted theatrical productions, most recently Creation Theatre's stark production of Orwell's '1984' and in particular we have provided an outlet for artists and photographers to display their work.

Michael Bonsall, Professor of Mathematical Biology at Oxford University's Department of Zoology, discusses his research in population biology, what it tells us about species evolution and, in particular, why grandmothering is important to humans. His research was done in conjunction with Oxford Mathematician Jared Field.

"What is mathematical biology?

Thu, 15 Jun 2017
16:00
C5

A discussion of Lurie's proof of the cobordism hypothesis

Adrian Clough
(Univerity of Texas at Austin)
Abstract

Despite its fame there appears to be little literature outlining Lurie's proof sketched in his expository article "On the classification of topological field theories." I shall embark on the quixotic quest to explain how the cobordism hypothesis is formalised and give an overview of Lurie's proof in one hour. I will not be able to go into any of the motivation, but I promise to try to make the talk as accessible as possible. 

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