Share this page!

Gro-Tsen Profile picture
Twitter logo
10 Feb, 5 tweets, 4 min read
Comme mes enseignements sont (pour l'instant) à distance, j'ai décidé de rendre publiquement accessible non seulement les notes des cours dont je suis responsable (c'était déjà le cas), mais aussi les enregistrements. Voici donc:
La séance de lundi 2021-02-08 de mon cours de «théories des jeux»: peertube.r2.enst.fr/videos/watch/7… (1re partie) et peertube.r2.enst.fr/videos/watch/0… (2e partie)
Le poly général de ce cours perso.enst.fr/madore/mitro20… et les pages annotées dans les vidéos ci-dessus: perso.enst.fr/madore/mitro20… ImageImageImageImage
La séance de ce matin 2021-02-10 de mon cours officiellement appelé «courbes algébriques» mais qui devrait surtout être une micro-introduction à la géométrie algébrique: peertube.r2.enst.fr/videos/watch/e… (1re partie) et peertube.r2.enst.fr/videos/watch/5… (2e partie)
Pas de poly pour ce cours-là, mais voici les notes gribouillées dans la vidéo ci-dessus: perso.enst.fr/madore/accq205… ImageImageImageImage

• • •

Missing some Tweet in this thread? You can try to force a refresh
　

Keep Current with Gro-Tsen

Gro-Tsen Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @gro_tsen

Gro-Tsen Profile picture
12 Feb
OK, I may be guilty of a DoS attack attempt on mathematicians' brains here, so lest anyone waste too much precious brain time decoding this deliberately cryptic statement, let me do it for you. •1/15
First, as some asked, it is to be parenthesized as: “∀x.∀y.((∀z.((z∈x) ⇒ (((∀t.((t∈x) ⇒ ((t∈z) ⇒ (t∈y))))) ⇒ (z∈y)))) ⇒ (∀z.((z∈x) ⇒ (z∈y))))” (the convention is that ‘⇒’ is right-associative: “P⇒Q⇒R” means “P⇒(Q⇒R)”), but this doesn't clarify much. •2/15
Maybe we can make it a tad less abstruse by using guarded quantifiers (“∀u∈x.(…)” stands for “∀u.((u∈x)⇒(…))”): it is then “∀x.∀y.((∀z∈x.(((∀t∈x.((t∈z) ⇒ (t∈y)))) ⇒ (z∈y))) ⇒ (∀z∈x.(z∈y)))”. •3/15
Read 15 tweets
Gro-Tsen Profile picture
11 Feb
Les bras m'en tombent.
Je n'utilise pas moi-même l'écriture «inclusive» (en tout cas pas habituellement) en français, et on ne me l'a jamais reproché, encore moins refusé de lire mes mails ou je ne sais quoi à cause de ça.
Je ne vois pas en quoi cette «écriture inclusive» pourrait être plus gênante que, disons, l'abus d'emojis ou de ponctuations, ou de locutions latines, ou aliud quidlibet.
Read 10 tweets
Gro-Tsen Profile picture
11 Feb
Hacking into company networks by providing public (and higher-numbered) “versions” of the internal packages they use:
And, of course, everyone was warned of this kind of problems long ago:
In various ways:
Read 4 tweets
Gro-Tsen Profile picture
10 Feb
I gave this a bit more thought: here are some interesting examples to have in mind (here, ring objects in some topos of sheaves): ⤵️
‣ The ring of Dedekind reals, which is represented by the sheaf of continuous ℝ-valued functions, in the topos of sheaves on many reasonable topological spaces (such as ℝ itself), satisfies ③ ∀x.(x=0⇔¬∃y.(x·y=1)) but fails ② ∀x.(¬(x=0)⇔∃y.(x·y=1)) (so fails ① too).
Indeed, x is invertible iff the continuous ℝ-valued function is everywhere ≠0, but it satisfies ¬(x=0) iff the function does not vanish on any nontrivial open set (so ② fails for a function vanishing somewhere but not on any nontrivial open set); …
Read 11 tweets
Gro-Tsen Profile picture
10 Feb
I've complained about this a number of times but not, I think, on Twitter: I am very much annoyed by the way many people call “game theory” a field which only includes stuff like normal form games, Nash/correlated equilibria, stochastic games, and the like, … •1/5
… but NOT combinatorial game theory (the Sprague-Grundy theory of games like nim, nor the Conway theory of partizan games), nor Gale-Stewart games and their determinacy, nor Ehrenfeucht-Fraïssé games, nor differential game theory, etc. •2/5
E.g., this online course, game-theory-class.org/game-theory-I.…‌, which calls itself “Game Theory”, no qualifiers added, doesn't mention any of the things listed in the previous tweet. So I guess the authors think they're not part of “game theory”? But then what are they? •3/5
Read 5 tweets
Gro-Tsen Profile picture
6 Feb
Let's take a second to ponder how marvelous the human brain is in its versatility and its ability to learn things it never evolved to do. ⤵️ •1/16
You're probably reading my words as squiggles on a computer screen. The absolutely incredible fact, here, is that these squiggles have ❋meaning❋, and your brain is able to decode these squiggles at an incredible speed to extract said meaning. •2/16
So the meaning travels from my brain to yours through an incredible convoluted, almost rube-goldberg-esque path of my moving my fingers to type keys on a keyboard and generate signals which then enter a very sophisticated electronic system which mankind designed, … •3/16
Read 16 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!

Like this author's thread?

Get emails when @gro_tsen has new unrolls!

Check out other threads from @gro_tsen!

Read all threads by @gro_tsen