I Love Shelah Embroidered Cap

A fair present for all of us in the profession:

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From amazon.com (they also have sweatshirts, caps, keychains and more). And no, I was not looking for a mug.

Mathe rockt

Pure, pure madness!

I am your good friend

On another occasion, Erdos met a mathematician and asked him where he was from. “Vancouver,” the mathematician replied. “Oh, then you must know my good friend Elliot Mendelson,” Erdos said. The mathematician replied, “I am your good friend Elliot Mendelson.”

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From “My brain is open ” by Bruce Schechter

Identity of indiscernibles

“Just take an ultrafilter D”
Saharon Shelah

“God is the Alexandroff compactification of the Universe”
Alexander Grothendieck

“Stone-Cech compactification of the Universe is the paganic polytheism”
Folklore

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Goedel’s formalization of ontological argument using ultrafilters and modal logic, see “Sobel on Goedel’s Ontological Proof” by Robert C. Koons

Incomparable degrees of unsolvability

I started talking with Post regularly. He gave me a batch of his reprints. John Stachel and I asked Post if we could do a reading course with him in mathematical logic. That was in my junior year. We didn’t get very far in the course, because Post had one of his breakdowns after a few weeks. He had just made an important discovery regarding incomparable degrees of unsolvability, and the excitement was too much for him and pitched him over into the manic phase. We didn’t see him again for some months.
…
Particularly logicians seem to be prone to it! In fact, I had a joke with John Stachel. Post had lost an arm in a childhood accident. Hans Reichenbach, who was sort of a logician and a philosopher, came to City College for a semester to give some courses, and he was essentially stone deaf. Church had vision problems—he had bad cataracts, which in those days was much more of a problem than it is today. So the joke was that, if I’m going to be a logician, maybe I should give up a finger now, instead of something worse!

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From the AMS Notices interview with Martin Davis.

Pêle-mêle

Sublime
Pêle-mêle
Henri Poincaré
D’élégants théorèmes
Prouva sans façons,

Classa des variétés
Difféomorphiquement
Utilisant la dualité
Et du génie aussi.

Autre
Pêle-mêle
Nicolas Bourbaki
Ressuscita de parmi les morts,
Pour les mathématiques sauver,

Débita d’assommants traités
Hypercinétiquement,
Prouvant qu’il aurait dû
Dans la tombe rester.

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Un exemple d’animosité envers Bourbaki est ce double poème d’un goût contestable écrit (en anglais) par Arnold Seiken.

Coordonnées

Soit une multiplicité vectorielle.
Un corps opère seul, abstrait, commutatif.
Le dual reste loin, solitaire et plaintif,
Cherchant l’isomorphie et la trouvant rebelle.

Soudain, bilinéaire, a jailli l’étincelle
D’où naît l’opérateur deux fois distributif.
Dans les rets du produit tous les vecteurs captifs
Vont célébrer sans fin la structure plus belle.

Mais la base a troublé cet hymne aérien:
Les vecteurs éperdus ont des coordonnées.
Cartan ne sait que faire et n’y comprend plus rien.

Et c’est la fin. Opérateurs, vecteurs, foutus.
Une matrice immonde expire. Le corps nu
Rentre en lui-mêm, au sein des lois qu’il s’est données.

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Sonnet composé par André Weil au congrès de Chançay (septembre 1937).

всё сливается в единое целое

…пусть каждый наш “персонаж” хочет выбрать себе не одну шляпу, а ДВЕ (на всякий случай оговорим, что количество экземпляров “шляп” у нас очень велико, и их всем хватает). Далее, будем считать, что каждый надевает на себя сначала одну “шляпу”, а потом другую, и в каждом случае делает “снимок” себя с надетой “шляпой”, который выглядит как некоторое дерево. Причём на снимке — это здесь самое главное — уже не видно, где кончается “шляпа”, и где начинается надевший её “персонаж”: всё сливается в единое целое…

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Falcao on the amenability of Thompson group.

Better late

Mai 1988 in Südfrankreich.

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From “In höheren Dimensionen” article by Winfried Scharlau (check out this awesome materials!).

Cantor opera

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Axel Köhler as Georg Cantor in the “Cantor - Die Vermessung des Unendlichen” opera by Ingomar Grünauer.