RAM et ultrafiltre

Title: Structures de réalisabilité, RAM et ultrafiltre sur N

Author: Jean-Louis Krivine

Abstract: We show how to transform into programs the proofs in classical Analysis which use the existence of an ultrafilter on the integers. The method mixes the classical realizability introduced by the author, with the “forcing” of P. Cohen. The programs we obtain, use read and write instructions in random access memory.

Illustrated guide to model theory: 2

(*) Every Man Needs A GOOD FORKING – Fridge Magnet

thank goodness

Shortly before the World War he [Zermelo] spent a night in the Bavarian alps. He filled the column “Nationality” in the hotel’s registration form with the words: “Not Swiss, thank goodness.”  Misfortune would have it that shortly after that the head of the Education Department of the Canton Zürich stayed at the same hotel and saw the entry. It was clear that Zermelo could not stay much longer at the University of Zürich.

(*) from Abraham Fraenkel’s “Lebenskrise”

Illustrated guide to model theory: 1

(*)  forkingfantastic.com

Topolozhstvo

in 1946, on the floor of the Academy of Sciences, Kolmogorov said something about his recent work on topology to Luzin, and the latter replied, “Eto ne topologiia, eto topolozhstvo” (“This is not topology, this is topolozhstvo“). Kolmogorov reddened and struck Luzin in the face. The word “topolozhstvo” is an invented term with a very clear meaning. In Russian the word skotolozhstvo means “bestiality,” while muzhelozhstvo means “sodomy.” Therefore, “topolozhstvo” was a word contrived by Luzin that might be translated as “topological pederasty.”

(*)

From “Naming Infinity” by Loren Graham and Jean-Michel Kantor

An interesting temporalization

Title: An interesting temporalization of Godel’s ontological proof;

Author: Gavriel Segre

Recent theologies concerning God’s death after Auschwitz are mathematically formalized through a suitable temporalization of Goedel’s Ontological Proof.

ZFC at hand

(*)

From the pretty amazing Science Tatoo Emporium freakshow

Stop worrying

Mariaahh

They would start about 9 P.M. when Tarski was just getting going. He always smoked, and he kept the door of his study closed so the smoke would stay in the room because he thought that made him concentrate better. “It was awful for me,” Chang said, “because I had asthma, but what could I do? I was his student. I wasn’t really a night person either and after a while it was a struggle to keep my eyes open. Around 2 A.M. he’d ask me if I wanted some coffee and I’d say yes. Sitting at his desk, with the door closed, he’d scream, ‘Mariaahh, Mariaahh,’, as loud as he could. If there was no answer, he’d repeat it, sometimes three or four times until Maria finally opened the door, half asleep, saying ‘Yes, Alfred?’ He’d ask her to bring us two cups of coffee and she trudged into the kitchen to make the coffee and bring it to us. I’ve never seen anything like it before or after.”

(*)

One of the many many many amazing stories from the “Alfred Tarski. Life and logic” by Anita and Solomon Feferman

Those of us working in this field are still a small band

This paper extends interplanetary trade theory to an interstellar setting. It is chiefly concerned with the following question: how should interest rates on goods in transit be computed when the goods travel at close to the speed of light? This is a problem because the time taken in transit will appear less to an observer traveling with the goods than to a stationary observer. A solution is derived from economic theory, and two useless but true theorems are proved.

(*)

From an abstract to “The theory of interstellar trade” by Paul Krugman, Nobel prize in economics 2008 winner.