Symplectic geometry in some sort of loose sense, you know, you hear it quite a lot and it floats around.  I'd been to Berkeley a lot where Weinstein talked about symplectic geometry and Kostant, MIT, talked about symplectic geometry. But it was all… most... most of that was at a fairly, sort of, formal elementary level, and nothing… I don't anything serious was going on.

So I think it probably was true that it was when I worked with Bott, that we... we got involved in it in a bit more serious way. And then I heard about… Mumford told me that what we were doing… how it fitted in with algebraic geometry, quotients and geometric invariant theory. And so it then began to become more seriously related with the topology and Frances Kirwan's work pushed it further. So I think it is true, that's the... that’s the first stage that I got involved with it. And of course the physicists… but then, when you talk to physicists, symplectic geometry is… well, I knew that it was… got of part of classical mechanics and is a kind of basis for quantum theory, but I'd never sort of played around with it in any serious way before myself; no, I think not.