Roger Penrose—a Personal Appreciation

Abstract Roger Penrose and I were research students together in Cambridge from 1952 to 1955. Moreover, we were both algebraic geometers at the time. I did my research under Hodge, and Roger, after starting with Hodge, moved over to work with Todd. In view of later events it is perhaps interesting to review briefly what areas our research was concerned with. Under Hodge I was steered towards differential geometry and topology. From Hodge’s book I learnt about harmonic forms and their origin in Maxwell’s equations, while from the work of the French school (Leray, Cartan, Serre) I learnt about sheaf cohomology. Although I had attended Dirac’s course on quantum mechanics it was not until some years later that I became acquainted with spin and the Dirac operator.