Tornare a Ventotene

I participated last week to the wonderful Ventotene 2017 Conference, a worthy continuation of Ventotene 2015. Reaching the island required this time even more of the stamina that the conference website recommends, since the weather was rough enough that the faster hydrofoil boat did not run (stranding about 30 of the participants in Formia on Sunday evening), while even the rather bigger one behaved more like a large scale roller-coaster than most people would wish.

After arriving at the island, Monday was still a bit unpleasant (it was much more for those who were unlucky to be exposed when one of the few short but very violent rain showers fell…), but the remaining of the time was beautiful. On the way back, I had to stop in Rome for a night, and tasted the most delicious ragù bianco di coniglio that one can imagine.

I’m already looking forward to the next conference…

A dragon of genus one

I just came back from Hong Kong, where I participated in a conference on automorphic forms and all their applications. Among the talks, I especially enjoyed to hearing about the current status of the Jacquet-Langlands correspondance from Badulescu, and also the definition and properties of uniform pro-$p$-groups in the talk of Jiu-Kang Yu.

I stayed two days after the conference and had time to do some visiting and shopping. My favorite browsing time was in the Yue Hwa Chinese Emporium (the address was suggested by Yuk-Kam Lau, who also suggested the restaurant where we had our best dinner). I couldn’t resist buying the torus-shaped box that I saw there.

According to my wife, this is certainly intended to hold necklaces and bracelets. It is decorated with a dragon and what I think is a phoenix (maybe representing two elements of a basis of the homology or cohomology of the torus). I haven’t yet measured it to check if it has complex multiplication.

I took a few animal pictures, although the rather oppressive weather made it a bit difficult to spend time walking leisurely outside.

And I saw a rather melancholy piano in a side street…

Musically, I think there is a minor modernist masterpiece to be written based on the rings, whistles and noises of the Octopus card system, recorded at one of the more important exits of the MTR subway at some of its busier hours of operation.

De l’inconvénient des usines à gaz

This is maybe for the cognoscenti, but rather funny:

The Norwegian Academy of Science and Letters announces the 2017 Abel Prize is awarded to Yves Meyer, École normale supérieure Paris-Saclay, France…

I’m even prouder now than before of having bought Meyer’s “Wavelets and operators” in the Peoria, Illinois, science museum store…

Ventotene

I just came back from a week on the Italian island of Ventotene, where I participated in a very nice conference on “Manifolds and groups”. This is of course not my usual topic, and besides giving a minicourse on expanders and coverings (with a focus on geometric applications of expanders having to do with coverings…), I learnt a lot of interesting things. I particularly enjoyed the other two minicourses, by T. Gelander on invariant random subgroups and by R. Sauer on Lücks’s Approximation Theorem. (For both of these, as well as for a number of other talks, the slides are available on the conference web page; my own — handwritten — notes on my course should appear there soon, after I scan them).

Being an island, Ventotene is reached by boat. One of the interesting things about the trip to Ventotene was to observe how birds

would follow us until a very definite point, and then suddenly disappear.

Also, the instructions to launch a lifeboat are rather daunting…

The organizers had scheduled a lot of free time during the conference besides the scientific programme. I was therefore able to take a few pictures, such as some of the local lizards,

and some of the wonderful local cats.

The end of the week also coincided with the beginning of the ten-day long celebration of the island’s patron saint, Santa Candida. Among the festivities were the evening launches

(over a week) of huge hot-air balloons (“Mongolfieri”), with some fireworks

(note the amusing effects of my camera’s fireworks scene setting without tripod…). Some Galois-theoretic persiflage was also notable…

Update The scans of my lectures can be found here.