I am now back from giving my Bourbaki lecture, and from attending the rest of the Bourbaki seminar on Saturday.

As usual, I enjoyed the lectures a lot (I was not entirely happy with mine; I’ve lectured a number of times now on sieve and expanders in some way or another, and I haven’t yet found the right way — which I’m sure exists! — of conveying the main point in a few crisp words or sentences…) It was a nice feeling to come in the Institut Henri Poincaré at 9:30 in the morning, and then come out at 5:00 in the afternoon, knowing that I now have some understanding of what the Kervaire invariant is, and why generalized cohomology theories might be useful (a nice talk by H. Miller about the work of Hill, Hopkins and Ravenel); that I have heard W. Werner explain some of the ideas of discrete complex analysis in S. Smirnov’s work; and that I could probably write down some basic definitions of control theory if I had to (a talk of O. Glass on work of J-M. Coron) — all things I knew next to nothing about the day before.

The Bourbaki seminar is now in its 63th year (the talks were numbered 1027 to 1030); long may it last!