## Fitting manifolds to data.

The problems come in two flavors.

Extrinsic Flavor: Given a point cloud in R^N sampled from an unknown probability density, how can we decide whether that probability density is concentrated near a low-dimensional manifold M with reasonable geometry? If such an M exists, how can we find it? (Joint work with S. Mitter and H. Narayanan)

## Topological filters: a toolbox for processing dynamic signals

## Toplogies of the zero sets of random real projective hyper-surfaces and of monochromatic waves.

## Exceptional holonomy and related geometric structures: Dimension reduction and boundary value problems.

## Exceptional holonomy and related geometric structures: Examples and moduli theory.

We will discuss the constructions of compact manifolds with exceptional holonomy (in fact, holonomy $G_{2}$), due to Joyce and Kovalev. These both use “gluing constructions”. The first involves de-singularising quotient spaces and the second constructs a 7-manifold from “building blocks” derived from Fano threefolds. We will explain how the local moduli theory is determined by a period map and discuss connections between the global moduli problem and Riemannian convergence theory (for manifolds with bounded Ricci curvature).