Author Archives: valuevar

About valuevar

I am a number theorist with side interests in combinatorics and group theory.

Expansion, divisibility and parity: an explanation

Posted on 2021/07/16 by valuevar

Back in March, I put a paper (joint with Maks Radziwill) up in the arxiv. It was 101 pages long (unsurprisingly, given that it was the outcome of several years’ worth of work) and may be a little hard-going. In … Continue reading →

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Hiring postdocs at Göttingen

Posted on 2017/12/01 by valuevar

I will be hiring two 2-year postdocs to work with me at Göttingen in the coming academic years. Please inform anybody you know who may be interested in this possibility. Apply as indicated in the advertisement. The deadline is December … Continue reading →

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Graph Isomorphism in Quasipolynomial time

Posted on 2017/01/17 by valuevar

My Bourbaki article on Babai’s algorithm for solving graph isomorphism in quasipolynomial time is now online. (Short story for those who have been following the matter in the last couple of weeks: Babai’s fix is both correct and elegant – … Continue reading →

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Bourbaki talk

Posted on 2017/01/14 by valuevar

This afternoon – Saturday, 4pm, Paris time – I will give a Bourbaki talk on the work of Babai on the graph isomorphism problem, going as well over previous work (Luks, Weisfeiler- Le(h)man, etc.) that prepared the way towards it. … Continue reading →

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Graph isomorphism in subexponential time

Posted on 2017/01/04 by valuevar

In the course of preparing my Bourbaki talk on Babai’s work on the graph isomorphism problem, I found an error. It is serious. Babai has succeeded in recovering a result that, while weaker, is still remarkable. Preparing a Bourbaki talk … Continue reading →

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Hangul and stinky tofu

Posted on 2015/02/22 by valuevar

It has been a while since I last wrote here. I might as well restart matters with a brief update. Summer was full of activities and travel. After giving a course at the summer school on analytic number theory at … Continue reading →

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Conference in Петербург

Posted on 2014/10/20 by valuevar

It is high time I told about my adventures in Korea at ICM (Hangul, stinky tofu, old and new friends) and about the very pleasant time I’ve been having in Saint Petersburg (maths, opera). But not yet! Let me first … Continue reading →

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Math people moving around

Posted on 2014/08/01 by valuevar

In the June 2014 issue of the Newsletter of the European Mathematical Society,there is an article (by Martin Andler, from Versailles) on the invited speakers at this year’s ICM, and, in particular, on geographical shifts in their career. Besides offering … Continue reading →

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AGRA II

Posted on 2014/03/03 by valuevar

I am now able to make this public: the second AGRA school (Aritmética, Grupos, Análisis) will be happening in Cusco in August 2015. Here is the website. We are still putting together funding, but we have already managed to ensure … Continue reading →

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Meta- and Galois

Posted on 2014/02/05 by valuevar

First, some extradiegetic comments. I did not post much last year. The main reason is obvious – for the first half of the year, I was very busy finishing the proof of the ternary Goldbach conjecture; then, during the summer, … Continue reading →

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