## Combinatorics of non-crossing partitions

## Deformation theory and 3-folds

This photo is of the blackboard in the common room of the School of Mathematics at the University of Edinburgh. The workings on the left are by Michael Wemyss, drawn while he was talking about deformation theory (a generalization of differential calculus) with Will Donovan, as part of their work on the geometry of certain spaces, known as 3-folds. Will says, “Deformation theory lets us express the way in which a curve in a 3-fold can `move’ infinitesimally: we can then relate this to the (quantum) geometry of the 3-fold. I’ve tried to emulate Michael’s calligraphic F’s and G’s, but I haven’t had any success yet.” We don’t know who did the workings on the right.

## The topology of algebraic varieties

Mikael Vejdemo-Johansson, from the University of St Andrews, sent in this photo some time ago, saying “we were discussing computational approaches to the topology of algebraic varieties, and sampling issues we were having. A very pleasantly geometric topic that generates a lot of sketches and pictures.”