- 9/14/2017: Collapsing co-associative fibrations
- 6/9/2017: 3+4 dimensional reductions of G
_{2}holonomy—collapsing and boundary value problems - 9/6/2016: Introduction to global questions around special holonomy
- 9/7/2016: Introduction to formal aspects of gauge and submanifold theory
- 9/9/2016: Adiabatic limits of coassocative fibrations

### September 14, 2017

TITLE: Collapsing co-associative fibrations

ABSTRACT: We will begin by explaining how “maximal” sub manifolds in spaces of indefinite signature arise as formal collapsing (or adiabatic) limits of manifolds with co-associative fibrations. Then we will discuss some analytical problems which arise in developing this idea, mostly having to do with the critical sets where the fibres become singular and the maximal submanifolds have branch points. In one direction we will discuss the deformation theory of these sets and in another we outline the relevance of recent constructions (by Yang Li and others) of new Calabi-Yau metrics on .

### June 9, 2017

TITLE: 3+4 dimensional reductions of G_{2} holonomy—collapsing and boundary value problems

ABSTRACT: The theme of the talk will be various simplifications of the equations defining holonomy structures, involving spaces that are fibred by either 3-dimensional or 4-dimensional manifolds. A central feature in these situations is an equation for “positive triples” of 2-forms over 4-manifolds, which is a generalisation of the hyperkahler condition. In one direction we will explain how this leads to a conjectural adiabatic limit of the equations for manifolds with co-associative “Kovalev-Lefschetz” fibrations, describing Riemannian collapsing to a 3-dimensional limit. In another direction we will discuss boundary value problems for positive triples and an extension of the Gibbons-Hawking construction, which leads to a formulation in terms of the Monge-Ampere equation on domains in .

### September 6, 2016

TITLE: Introduction to global questions around special holonomy

### September 7, 2016

TITLE: Introduction to formal aspects of gauge and submanifold theory