## Archive for the ‘**Symplectic geometry**’ Category

## Kronheimer’s argument: Small resolutions and Dehn twists

I want to amplify an expository argument I gave in a recent lecture which shows that the squared Dehn twist on a symplectic 4-manifold is smoothly isotopic to the identity map. This is an old argument of Kronheimer and I only managed to sketch it hurriedly in the lecture. A few people have asked me to explain this to them in the past, so here’s an explanation to which I can point people in future.

## Symplectic/Contact Geometry VII at Les Diablerets, Day 1

I’m currently in Switzerland at the seventh “Symplectic Geometry, Contact Geometry and Interactions” Workshop funded by CAST. This is a yearly conference which started at the same time I started my PhD so I have a great fondness for these workshops. This one is in the mountains, which makes me even fonder…

After three excellent talks today I decided to act as a “maths journalist” and summarise the main ideas from the talks in this blog. I may not be able to keep this up, as there’s six talks tomorrow and too much snow to enjoy. Today’s talks were: