Probability plays a major role, and there are corresponding differences for martingales.
More recently, with Catherine Finet, I have studied the difference in higher dimensions between spaces of functions and martingales related to the Riesz transform and the Dirac operator and the harmonic case. At present active research has taken a back seat. I am seconded part-time to the London Mathematical Society, where I am Executive Secretary. The London Mathematical Society is active in promoting research, and I am able to further this activity.