There will now be a second mirror workshop of ABC in Grenoble. Taking place at the Université de Montpellier, more precisely at the Alexander Grothendieck Montpellier Institute, Building 9, room 430 (4th floor), Triolet Campus. It is organised by my friend Jean-Michel Marin. Great to see a mirror at one of the major breeding places of ABC, where I personally heard of ABC for the first time and met several of the main A[B]Ctors..! The dates are 19-20 March, with talks transmitted from 9am to 5am [GMT+1]. Since the video connection can accommodate 1918 more mirrors, if anyone else is interested in organising another mirror, please contact me for technical details.

## Archive for Alexandre Grothendieck

## another mirror of ABC in Gre[e]noble

Posted in Statistics with tags ABC, ABC in Grenoble, Alexandre Grothendieck, Approximate Bayesian computation, Grenoble, INRA, likelihood-free methods, mirror workshop, population genetics, Université de Montpellier, videoconference on March 3, 2020 by xi'an## prime suspects [book review]

Posted in Books, Kids, University life with tags Alexandre Grothendieck, book review, CHANCE, comics, François Schuiten, Gödel Escher and Bach, graphic novel, Jacques Tardi, José Muñoz, Kingman's coalescent, logicomix, NCIS, Nicolas Bourbaki, Persi Diaconis, Princeton University Press on August 6, 2019 by xi'an**I** was contacted by Princeton University Press to comment on the comic book/graphic novel Prime Suspects (The Anatomy of Integers and Permutations), by Andrew Granville (mathematician) & Jennifer Granville (writer), and Robert Lewis (illustrator), and they sent me the book. I am not a big fan of graphic book entries to mathematical even less than to statistical notions (Logicomix being sort of an exception for its historical perspective and nice drawing style) and this book did nothing to change my perspective on the subject. First, the plot is mostly a pretense at introducing number theory concepts and I found it hard to follow it for more than a few pages. The [noires maths] story is that “forensic maths” detectives are looking at murders that connects prime integers and permutations… The ensuing NCIS-style investigation gives the authors the opportunity to skim through the whole cenacle of number theorists, plus a few other mathematicians, who appear as more or less central characters. Even illusory ones like Nicolas Bourbaki. And Alexander Grothendieck as a recluse and clairvoyant hermit [who in real life did not live in a Pyrénées cavern!!!]. Second, I [and nor is Andrew who was in my office when the book arrived!] am not particularly enjoying the drawings or the page composition or the colours of this graphic novel, especially because I find the characters drawn quite inconsistently from one strip to the next, to the point of being unrecognisable, and, if it matters, hardly resembling their real-world equivalent (as seen in the portrait of Persi Diaconis). To be completely honest, the drawings look both ugly and very conventional to me, in that I do not find much of a characteristic style to them. To contemplate what Jacques Tardi, François Schuiten or José Muñoz could have achieved with the same material… (Or even Edmond Baudoin, who drew the strips for the graphic novels he coauthored with Cédric Villani.) The graphic novel (with a prime 181 pages) is postfaced with explanations about the true persons behind the characters, from Carl Friedriech Gauß to Terry Tao, and of course on the mathematical theory for the analogies between the prime and cycles frequencies behind the story. Which I find much more interesting and readable, obviously. (With a surprise appearance of Kingman’s coalescent!) But also somewhat self-defeating in that so much has to be explained on the side for the links between the story, the characters and the background heavily loaded with “obscure references” to make sense to more than a few mathematician readers. Who may prove to be the core readership of this book.

There is also a bit of a Gödel-Escher-and-Bach flavour in that a piece by Robert Schneider called Réverie in Prime Time Signature is included, while an Escher’s infinite stairway appears in one page, not far from what looks like Milano Vittorio Emmanuelle gallery (On the side, I am puzzled by the footnote on p.208 that “I should clarify that selecting a random permutation and a random prime, as described, can be done easily, quickly, and correctly”. This may be connected to the fact that the description of Bach’s algorithm provided therein is incomplete.)

*[Disclaimer about potential self-plagiarism: this post or an edited version will eventually appear in my Books Review section in CHANCE. As appropriate for a book about Chance!]*

## Garrigue administrative

Posted in Books, pictures, University life with tags AI, Alexandre Grothendieck, automated document analysis, mathematics, Université de Montpellier on May 20, 2019 by xi'an**A** central page in Le Monde of this week (May 08), about the conundrum of dealing with the dozens of thousands of handwritten pages left by Alexandre Grothendiek, from trying to make sense of the contents to assessing the monetary value (!) of such documents. Mentioning that the most reasonable solution would be to extend the numerisation of earlier documents supervised by Jean-Michel Marin. Given the difficulty in reading these pages, as suggested by Le Monde, training an AI to translate them into regular text would make sense, if not helping with evaluating their importance…

## Grothendieck’s papers on-line!

Posted in Books, Kids, University life with tags Alexandre Grothendieck, mathematics, notes, Université de Montpellier on May 10, 2017 by xi'an**T**oday, the University of Montpellier will put on-line the series of 18,000 pages of manuscripts of Alexandre Groethendieck that it had digitised a few years ago. Thanks to the efforts of Jean-Michel Marin, the nearly incomprehensible legal imbroglio on the rights of both the University and the children of Groethendieck has been unravelled, meaning that the University is now allowed to make the manuscripts available, while the children have the sole property of the dozens of thousands of pages written by Groethendieck till his death. It is hard to imagine how such a volume can be efficiently explored and exploited to uncover new mathematical advances made by Groethendieck in the last and secluded part of his life, but at last the raw material is available for all to try.

## The Grothendieck papers

Posted in Books, Kids, Mountains, pictures, University life with tags Alexandre Grothendieck, Bibliothèque Nationale, BNF, IHES, Jean-Michel Marin, Lassere, Montpellier, national treasure, succession on December 28, 2016 by xi'an**F**ollowing the death of the mathematician Alexandre Grothendieck in 2014, his former maths department at the University of Montpellier decided to digitise in very high resolution the 28,000 pages of notes he had left to the department. Under the supervision of Jean-Michel Marin, Head of the said department! However, thanks to the French laws governing succession, those notes cannot be posted on-line without the authorisation of the five children of Grothendieck, who keep a moral right on those notes, even though they were given to the department. Grothendieck’s children want to recover all their father’s notes—which amount to more than 90,000 handwritten pages—presumably towards a bulk sale to a prestigious American university, but the succession is in limbo while the monetary value of those notes is not ascertained. And the digitised notes are stuck in this legal no man’s land as well. It is fairly ironical that those notes are at the centre of a financial conundrum, when Grothendieck’s anarchist principles led him to refuse awards and positions and to lead a recluse and frugal life in an isolated mountain village. And to prohibit the publication of those notes… Jean-Michel remains confident though that a solution can soon be reached between Grothendieck’s children, the University, the IHES, and the French National Library. I hope those notes can be made public, so that anyone could consult them. In paper or digitised format. Even though most of these pages may just be unexploitable. But at least they will be available rather than stuck in a storage for another 25 years.