@antoinechambertloir@mathstodon.xyz avatar

antoinechambertloir

@antoinechambertloir@mathstodon.xyz
  • Apprentice mathematician (Professor at Université Paris Cité),
    interested in algebraic geometry, number theory and (more recently) proof formalization
  • Apprentice musician (drums, tabla, cajon; previously Diderock; a rarely meeting jazz trio/quartet).
  • Apprentice progressist.

In love with math, jazz, indian music and poetry. ⏚

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averell, to random French
@averell@oc.todon.fr avatar

Et voilà la première vidéo : Hey Joe !
Avec l’aide inestimable de @antoinechambertloir à la batterie, qui a réussi à reprendre le poste de main de maître en moins d’une semaine. https://peertube.gegeweb.eu/videos/watch/400987dd-3a1e-4d47-94cd-d9df3cc38dce

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@averell Voilà, on lit un message sur mastodon un dimanche matin et 8 jours plus tard on se retrouve sur peertube !
Merci de votre invitation ! C'était cool de faire votre connaissance et de jouer avec vous !

antoinechambertloir, to random French
@antoinechambertloir@mathstodon.xyz avatar

Juge pas mon genre: En France, chaque année, des centaines de personnes trans doivent encore passer par les tribunaux pour changer la mention du sexe qui apparaît sur leurs papiers d’identité.

Il faut mettre en place un changement de sexe à l’état civil qui soit déjudiciarisé, libre et gratuit pour toutes les personnes trans, et qui puisse se faire sur simple demande.

https://chng.it/GGW8vGGMYW

antoinechambertloir, to random French
@antoinechambertloir@mathstodon.xyz avatar

@lelibreedu
Bonjour, j'ai une question sur les ordinateurs confiés aux lycéen·nes: il n'y a dessus quasi pas de logiciel pour taper du code, juste le bloc notes et un autre similaire. N'y aurait-il pas intérêt à mettre quelque chose de plus avancé, même vscode, d'autant plus qu'il est apparemment impossible/interdit d'installer quoi que ce soit soi-même.

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@bmarne @Matthieu2villR @nicolay_lilicre @lelibreedu

Notepad++ a l'air d'être le truc installé; il ne m'avait pas l'air des plus pratiques, d'où ma question…

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@Bibobu @bmarne @Matthieu2villR @nicolay_lilicre @lelibreedu

Pas faux… mais un éditeur qui aligne correctement, fait un peu de syntax highlighting, etc., ça serait bien. Peut-être j'ai raté des trucs sur sa machine.

antoinechambertloir, to random French
@antoinechambertloir@mathstodon.xyz avatar

Déficit public: "Ce n'était pas prévisible", estime Jean-René Cazeneuve (député Renaissance, rapporteur général de la Commission des Finances)

Déficit public encore: "Il faudra s'attaquer au statut de la fonction publique", estime Éric Ciotti (président des Républicains)

(insérer émoji fourche, hallebardes, guillotine, Hitchcock…)

antoinechambertloir, to random French
@antoinechambertloir@mathstodon.xyz avatar

C'est cool la messagerie ENT du lyée qui se fait hacker, quand les élèves ont perdu l'habitude d'avoir un cahier de textes et que tout est sur une appli indisponible parce que l'ENT est bloqué tout le week-end…
À part ça, on peut porter plainte pour défaut de prudence, insuffisance de moyens, quand une application web obligatoire de l'Éducation nationale met des jeunes en contact avec des contenus violents ?

krazykitty, to random French
@krazykitty@mamot.fr avatar

Eh bien ce concert autour de Gérard Caussé, supposé mettre en valeur l'alto, était un très beau plaidoyer pour la retraite. Il a été un grand altiste (il est toujours très grand (pardon (en même temps à côté de Renaud Capuçon))), il a bien mérité de passer ses journées à lire le journal et promener son petit chien maintenant.

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@krazykitty @MatsuBasho
Ça arrive...
C'est en entendant des concerts de jazz qui s'étaient annoncés prodigieux (McCoy Tyner...) que j'ai accepté que la musique vivante ne pouvait pas être parfaite.
Et peut être qu'elle ne doit pas l'être.
Cela dit, c'est frustrant.

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

There are a lot of deep conjectures about L-functions. For example, there’s the Langlands program. And the Riemann Hypothesis counts too, because the Riemann zeta function is the grand-daddy of all L-functions! But there’s also a million-dollar prize for proving another conjecture about L-functions. It's called the Birch-Swinnerton and Dyer Conjecture, and it's about L-functions of elliptic curves.

So if you want to learn about this stuff, you may try to learn the definition of an L-function of an elliptic curve. And if you go someplace like Wikipedia, you'll immediately hit an obstacle: the definition is very complicated.

In fact it's so complicated that I figured there's no way this can be the real definition. I started simplifying it a bit here:

https://golem.ph.utexas.edu/category/2024/03/counting_points_on_elliptic_cu.html

But I guessed I could simplify it a lot more.

(1/3)

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@johncarlosbaez There is a serious difficulty in your definition, that if you have an elliptic curve E over Q,
E(Z), E(Z/nZ) do not make sense a priori.
In fact, a great deal of work is needed to explain what this means, independently of the initial equation (which can have denominators). This can be done by hand for elliptic curves, see Tate's formulaire (written by Deligne, in the Antwerp volumes on modular forms), or abstractly, invoking the “Néron” model (which, for elliptic curves, predates Néron, of course).

But of course, you recovered the initial work of Hasse and Weil, who defined the zeta function of a system of equations (=scheme of finite type) over Z, and, in the case of elliptic curves, took out the zeta factors.

What is miraculous is that these delicate factors are exactly the ones which will furnish a nice functional equation, L(s)<->L(2-s).

In the 60s, Serre worked a lot to guess how to define correctly the zeta function of a variety over Q, especially the bad factors, when guessing a good system of equations over Z is hopeless, in terms of the Galois representations associated with the variety.

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@johncarlosbaez But there are no elliptic curves over Z, at least in the accepted terminology.
By definition, elliptic curves over a ring behave like families of elliptic curves, it has to be proper and smooth (in the terminology of differentiable manifolds, a submersion with compact fibers).
(And even, Jean-Marc Fontaine showed that there are no abelian varieties over Z.)

I believe Hasse's work where some “Hasse-Weil” zeta function appears is that one. (Apparently, he had suggested the question to Pierre Humbert.) He couldn't have the definition you propose:

“Eine entsprechende Analogisierung der Reihendefinition der Zetafunktion von K
erscheint nicht möglich, weil man in K zwar eine eindeutige Primdivisorzerlegung, nicht
aber auch eine eindeutige Punktzerlegung hat.”

but once schemes were there, it was possible to exhibit what Hasse wanted.

https://sci-hub.st/https://doi.org/10.1515/9783110835007.450

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@macbro @johncarlosbaez Even that is not enough. You can modify the curve over Z in a fairly large number of ways, this will totally change the zeta function, it will lose the functional equation, etc. but it should not.

ciredutempsEsme, to random French
@ciredutempsEsme@mamot.fr avatar

Est ce que vos enfants ont le droit de se tromper ? De se planter ?
Êtes vous prêts à cette éventualité ?

antoinechambertloir,
@antoinechambertloir@mathstodon.xyz avatar

@scudery @ciredutempsEsme Il y a un roman poignant de Doris Lessing sur la question, Le cinquième enfant…

antoinechambertloir, to random French
@antoinechambertloir@mathstodon.xyz avatar

Capes d'allemand pour n⁰2. Send hugs.

YVioujard, to random French
@YVioujard@piaille.fr avatar

deleted_by_author

    •
    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar

    @YVioujard @scudery @ciredutempsEsme ... Et surtout affecter d'urgence les soldats US mobilisés pendant la première guerre mondiale.
    Autrement dit, dune mesure imparfaite mise en œuvre dans un but conjoncturel et précis, faire une notion « scientifique » de l'intelligence .

    LegalizeBrain, (edited ) to random French
    @LegalizeBrain@mastodon.zaclys.com avatar

    deleted_by_author

    •
    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar

    @LegalizeBrain Ah, 2012, pas 2018 !

    antoinechambertloir, to jazz French
    @antoinechambertloir@mathstodon.xyz avatar

    There was a guy named Maxwell,
    who was born on that day, 100 years ago,
    even if his birth certificate doesn't say so.
    His second name was Lemuel.
    Whatever — everybody calls him Max.
    Let's embark for a 100 days celebration
    with Max Roach, here on Mastodon.
    You know what to do? — Follow the hashtag…

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. Ode From Black Picture Show

    It's a solo piece, by Max Roach only.
    A piece he composed and sings and plays at the piano.

    The lyrics are taken from an anonymous nursery rhyme, “There was a man of double deed”, which seems to be simultaneously well known and mysterious — nothing makes sense, except for our final death…

    Roach turns it into a torchy lament.

    https://www.youtube.com/watch?v=gJQ5b1o5dRI

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. The Martyr, Pt 1.

    This is a very long track, more than 30 minutes, composed by Max Roach, recorded in quartet in 1977.
    Reggie Workman at the bass starts with a great riff and Billy Harper (tenor sax) and Cecil Bridgewater (trumpet) share the joy of improvising on this melody, while Roach pushes the band with a forceful energy.
    After 8 minutes, the mood changes for a bass chorus that lasts 7 minutes, with rare interventions by the trumpet. The drum chorus that follows a second exposition of the theme is full of energy, yet melodic. As often with this quartet, the sax chorus escapes (so it seems, at least) the melody which it recalls occasionally. A new drum chorus in a different style, using drum rolls to provide long sounds, and toms to infer melodies. The rhythmic structure of the theme can be felt all along, and it's as if Roach is never bored, nor tired of playing this incredible melody. A last bar, a rim shot, and the musicians give a final version of the theme.

    https://www.youtube.com/watch?v=6V53wnyPgfc

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. Six Bits Blues

    The same album as yesterday, The Loadstar, features this beautiful, heart-rending, slow blues, also composed by Roach, which is so slow that the triplet decomposition of the beat gives a 3/4 feel. As for yesterday, the musicians take the opportunity of playing the tune live to expand it to a long 20 minute piece, so I felt more natural, and maybe more indulging to you, to suggest the 1981 version, in Chattahoochee Red, which lasts only 4 minutes. (Of course, that means you'll be deprived of a beautiful bass chorus.)

    https://www.youtube.com/watch?v=8WQR512n3eQ

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. The Dream / It's Time

    The album Chattahoochee Red contains pieces of all kinds, and the one that opens the volume is a drum improvisation by Max Roach on top or Martin Luther King Jr's 1963 speech at the Lincoln memorial, “I Have A Dream”.

    After the final “Free At Last”, the quartet goes on with Max Roach's composition “It's Time”.

    Is there anything more to say?

    https://www.youtube.com/watch?v=JxneNQUMcCc

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. Symbols

    A free improvisation duet with Connie Crothers, on piano, recorded in NYC, 1982.

    Born in 1941, Connie Crothers was an American pianist, a student of Lennie Tristano. She recorded a twentieth of albums in the years 1980 up to her death in 2016.

    Of course, since this is free improvisation, there's no apparent melody, no systematic groove. Despite Roach's constant engagement in avant-garde music, it seems he didn't involve in that musical form except for that recording. I find interesting that he doesn't impose his traditional licks, but simply tries to cooperate with Crothers. Discovering that album as I prepare this post, I'll definitely spend some time listening to her music.

    https://www.youtube.com/watch?v=kntGMbEUi2c

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. Ruby My Dear

    A Thelonious Monk ballad, here played by Max Roach Quartet, from the 1983 In the light album.

    Anyway, it is essentially Cecil Bridgewater (trumpet) that we hear, with a light drumming on brushes and, especially when the chorus starts, a bass line by Calvin Hill, and to conclude, a second line on saxophone by Odean Pope.

    That's a very humble and melancholic version. Ruby was Monk's first love.

    https://www.youtube.com/watch?v=bQLTuJXyo7s

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. Straight No Chaser

    From the same album as yesterday, let's listen to a second composition by Thelonious Monk, that time, a fast be bop.
    The exposition of the theme is played in relatively classic way, but the choruses definitely take their inspiration elsewhere, already on trumpet and even more on saxophone. Still, Max Roach's chorus is rigorously built on the structure of the melody, a 12 bar blues, the changes of the melody and its rhythmic patterns.

    https://youtu.be/ZEX7kr81g6w

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. Perdido

    A Live in Berlin album by the same quartet, recorded in 1984. The song is a bop classic, a composition of Juan Tizol, the famous trombone player in Duke Ellington's band, and also a composer of great songs, of that one, as well as of Caravan.

    Nevertheless, the style in which the musicians explore the song is definitely different from the early be bop era. While bass (Tyrone Brown) and drums (Max Roach) provide a consistent and regular groove, trumpet (Cecil Bridgewater) and saxophone (Odean Pope — but the cover says Odeon…) propose kind of a deconstructed version of the classic theme. The second lines are not just here as an ornament, but more as if there were two voices, sometimes in par, sometimes dissonant.

    The bass solo is excellent, and when it's time for a drum solo, it is amazing how Roach uses silence to create expectation.

    https://www.youtube.com/watch?v=MNEeBZ8B4x4 (edit: wrong YT link)

    antoinechambertloir,
    @antoinechambertloir@mathstodon.xyz avatar
    1. Mr Seven

    One more piece by M'Boom, from their third album Collage.

    It is called Mr Seven because it is based on an infectious 7/8 groove—the composer is Warren Smith.

    Max Roach plays vibraphone, Kenyatte Abdur-Rahman is on bass drum and xylophone,
    Eddie Allen on bell tree, cabasa, cymbal, Eli Fountain on bells, drum and snare, Ray Mantilla on bells, Joe Chambers on marimba, Fred King on timpani, Roy Brooks on tom tom, Freddie Waits and Warren Smith play “various percussion”!

    Will you dance?

    https://www.youtube.com/watch?v=PEUs_9KVFc0

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