Finally, a joy

In Rome we have an expression, mai una gioia (literally, “never (a moment of) joy”) that applies well to the present times. Yesterday, there was, finally, something to be joyous about: the announcement that two of my heroes, Laszlo Lovasz and Avi Wigderson, will share the 2021 Abel Prize, one of the highest honors of mathematics.

The reader can find a very good article about them on Quanta Magazine.

Instead of talking about their greatest accomplishment, here I would like to recall two beautiful and somewhat related results, that admit a short treatment.

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Silver linings

To put it mildly, 2020 is not shaping up to be a great year, so it is worthwhile to emphasize the good news, wherever we may find them.

Karlin, Klein, and Oveis Gharan have just posted a paper in which, at long last, they improve over the 1.5 approximation ratio for metric TSP which was achieved, in 1974, by Christofides. For a long time, it was suspected that the Held-Karp relaxation of metric TSP had an approximation ratio better than 1.5, but there was no viable approach to prove such a result. In 2011, two different approaches were developed to improve 1.5 in the case of shortest-path metrics on unweighted graphs: one by Oveis Gharan, Saberi and Singh and one by Momke and Svensson. The algorithm of Karlin, Klein and Oveis Gharan (which does not establish that the Held-Karp relaxation has an integrality gap better than 1.5) takes as a starting point ideas from the work of Oveis Gharan, Saberi and Singh.

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What’s New

It has been six weeks since I moved to Milan, and I am not yet completely settled in yet.

For example, although, as of yesterday, I finally have working wired internet access in my place, I still do not have a bus card (obtaining the latter has been one of the most stubbornly intractable problems I have encountered) and all the stuff that I did not carry in two bags is still in transit in a container.

Meanwhile, the busyness of handling the move, getting settled, trying to get a bus card, and teaching two courses, has meant that I did not really have time to sit down with my thoughts and process my feelings about such a major life change. If people ask me what I miss about San Francisco I will, truthfully, say something like UberX, or Thai food, or getting a bus card from a vending machine, because I still have not had a chance to miss the bigger stuff. Similarly, this post will be about random small stuff.

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Knuth Prize to Avi Wigderson


Congratulations to the Knuth prize committee chaired by Avrim Blum for the excellent choice of awarding the 2019 Knuth prize to Avi Wigderson.

Avi has worked on all aspects of computational complexity theory, and he has had a transformative influence on the way theoretical computer science relates to pure mathematics. I will not repeat what I wrote about his work on the occasion of his 60th birthday here and here. Long-term readers of in theory will remember that I consider him as one of the saints of computational complexity.

The organizers of the coming FOCS would like me to remind you that the deadline is this Friday, and that someone, for some reason, has set up a fake submission site (on the domain aconf dot org) but the true submission site (that, to be honest, looks less legit than the fake one) is at

Also, the deadline to submit nominations for the inaugural FOCS test of time award is in three weeks. There will be three awards, one for papers appeared in FOCS 1985-89, one for FOCS 1995-99 and one for FOCS 2005-09.

On an unrelated note, GMW appeared in FOCS 1986 and the Nisan-Wigderson “Hardness versus randomness” paper appeared in FOCS 1988.

Tested by time

I was delighted (and not at all surprised) to hear that this year’s Turing Award will go to LeCun, Hinton, and Y. Bengio for their work on deep learning.

Like public-key cryptography, deep learning was ahead of its time when first studied, but, thanks to the pioneering efforts of its founders, it was ready to be used when the technology caught up.

Mathematical developments take a long time to mature, so it is essential that applied mathematical research be done ahead of the time of its application, that is, at a time when it is basic research. Maybe quantum computing will be the next example to teach this lesson.

By the way, this summer the Simons Institute will host a program on the foundations of deep learning, co-organized by Samy Bengio, Aleks Madry, Elchanan Mossel and Matus Telgarsky.

Sometimes, it is not just the practical applications of a mathematical advance that take time to develop: the same can be true even for its theoretical applications! Which brings me to the next announcement of this post, namely that the call for nominations for the FOCS test of time award is out. Nominations are due in about four weeks.

Guest post by Chris Brzuska: LGBTQIA Meeting at Eurocrypt

[I was delighted to receive the following guest post by Chris Brzuska about a meeting that took place last week during Eurocrypt in Tel Aviv. This piece will also appear in Omer Reingold’s blog. Let me take this opportunity for a couple of shoutouts. Next week it’s going to be two years since Italy, last among Western European countries, has instituted same-sex civil unions (yay!) and the parties that opposed it now have an absolute majority after the last elections (boo!). The Berkeley EECS department has an LGBT+ graduate student organization called QiCSE that organizes a very visible breakfast meeting during the visit days for prospective grad students and regular meetings during the school year – as much as I value Berkeley exceptionalism, think about creating something like this in your own school. It would be great if there was a LGBT+ meeting at STOC this year; I am not going to STOC this year, but maybe someone else can take the lead. And now, on to Chris’s beautiful essay. Congratulations, Chris!. — Luca]

I gender-transitioned two years ago, and Eurocrypt 2018 in Tel-Aviv is the first major conference I attend since then. I am a bit nervous. How much time does it take for 400 people to update my name and pronouns to use “Chris” and he/him? Two years feels like an eternity to me, but surely, some people will not have heard about my gender-transition. I will need to come out to some people.

Coming-out is very empowering, but after two years and uncountable coming-outs, I really wish that everyone knows that I am trans and gay.

A gay friend of mine remarks that when being bisexual/lesbian/gay, coming out is really never over, and one needs to come out again and again, to each new person. And really, he says, there is rarely a good time to bring it up.

“How come you didn’t know I am lesbian/gay?”, I heard from several friends, in shock, worried I might have wrongly assumed they are heterosexual.

How many LGBTQIA people are in our communities? I know some LGBTQIA people in the community, but how many more are there, and how can I find them?

This simple question leads to something which would become more important to me than I expected initially.

In the rump session, I give a coming-out talk, combined with an announcement for an LGBTQIA cryptographers meeting during the rump session break (

Giving this talk in itself was very nice. I enjoyed sharing my happiness with the community, see my happiness reflected in other people’s eyes. I enjoyed the many positive comments I received during the hours and days that followed, and the recognition of daring to be visible.

During the break, I am excited and nervous. How many people will come to the meeting? And who? More than 10 people come, most of which I knew without knowing they are LGBTQIA. We walk into the room, one by one, each with light in our eyes. We came out to each other, all of us, in that moment. It’s intimate, moving, exciting. Coming out remains deeply personal. It can be daunting, even in a warm, progressive environment such as our research community and even to an LGBTQIA subgroup.

After the rump session, we go to the gay-lesbian bar Shpagat in Tel-Aviv, in happy excitement. We are the last customers that night. The next day, during the breaks, we often find ourselves with a majority of LGBTQIA people in a conversation, we sit next to each other during talks. Something important happened.

In light of our increased visibility (to each other and to the community at large), there were more opportunities for coming outs the next days (or so was my impression, although I am only conscious of 2 explicit cases…). It was very liberating for me to share many of the following conference moments with LGBTQIA cryptographers who would add additional views to a heterosexual, cissexual perspective, and who would help me explain the sensitive issue of coming out to other caring members of our research community.

The research community is my permanent country of residence, my frame of reference, the source of almost all my long-term friendships – and enfin, in this country, there live quite a few LGBTQIA people, and the research community encourages us and shares our happiness.

We are going to organize more LGBTQIA meetings alongside cryptography-related conferences. I hope, there will be more such meetings inside and outside of CS. And we look forward to see the number of LGBTQIA researchers (that we are aware of) grow.

If you are an LGBTQIA researcher who wants to get in touch with us more discretely than at a public meeting (to talk to one of us, e.g., in the beginning of your PhD etc.), you can send an eMail to You can also use that eMail address to join our mailing list (for event announcements) and/or our WhatsApp group (include your phone number if you want to join the WhatsApp group). While the group centers around cryptography-related events, the group is not limited to researchers in cryptography.

Annuntio vobis gaudium magnum: habemus directors

(Photo credit: ACM)

Formally ending a search started in March 2016 (and a process started in the Fall of 2015), we are pleased to finally officially announce that Shafi Goldwasser will take over from Dick Karp as director of the Simons Institute for Computing on January 1st, and will return to Berkeley after a 30+ year hiatus.

Shafi is the co-inventor and developer of the notions semantic security in encryption; of zero-knowledge proofs; of pseudorandom functions; of the connection between PCP and hardness of approximation; and of property testing in sublinear algorithms, among others. She has received the Turing award for her work on cryptography and of two Gödel prizes for her work on complexity.

I cannot put in words how happy I am for the Berkeley community, including myself, and for the future of the Institute.

The director search was my first glimpse into how the Berkeley central campus bureaucracy operates, and it was horrifying. The simplest thing couldn’t be done without a sequence of authorities signing off on it, and each authority had a process for that, which involved asking for other things that other authorities had to sign off on, and so on in what at times seemed actual infinite descent.

The announcement linked above was in the works for at least three weeks!

Alistair Sinclair, after two terms as associate director of the Simons Institute, during which his heroic efforts were recognized with the SIGACT service award, also retired from his position at the Institute, and last July 1st was replaced by Berkeley professor Peter Bartlett, a noted pioneer of the study of neural networks.

This weekend, on Saturday, the Simons Institute will host the FOCS reception, which will double as celebration for Alistair’s prize. There will buses leaving the conference hotel at 6:45pm, and there will be plenty of food (and drinks!) at the Institute. There will also be buses taking people back to the hotel, although once you are in downtown Berkeley on a Saturday evening (bring a sweater) you may want to hang out a bit more and then take a rideshare service back to the hotel.