University of Calgary
UofC Navigation

Richard Zach's blog

Milton Friedman and Gödel

Submitted by Richard Zach on Tue, 09/23/2014 - 10:51am

I've been having a conversation with Alex Douglas and Eric Schliesser on their posts (Alex's, Eric's) about Milton Friedman's footnote about observer-dependence and Gödel's incompleteness theorem.

John Venn Day

Submitted by Richard Zach on Mon, 08/04/2014 - 2:21am

John Venn would have been 180 today (August 4). In celebration, Google put up an interactive Venn Diagram doodle, which is pretty amazing.

Also, TIL that it's not a Venn diagram if it doesn't contain all possible intersections, a restriction that doesn't apply to Euler diagrams.  So representing an empty intersection by two non-intersecting regions is, technically, not a Venn diagram; and Venn diagrams for more than three sets get harder and harder to draw. Check out the informative Wikipedia entry.

I have a previous entry on humorous Venn (and Euler) diagrams around the Internets.

Gödel's Vienna: Finding Café Reichsrat

Submitted by Richard Zach on Thu, 07/24/2014 - 3:51am

The Café Reichsrat in Vienna is notable as the place where Gödel, on August 26, 1930, first announced the incompleteness theorem to Carnap, Feigl, and Weismann. The members of the Vienna Circle had met there to prepare for the trip to the "Zweite Tagung für Erkenntnislehre der Exakten Wissenschaften," a satellite meeting to the congress of the German Society of Mathematicians organized by the Vienna Circle. This was where the famous symposium on the foundations of mathematics took place, with Carnap representing logicism, Heyting intuitionism, and von Neumann speaking for Hilbert's school of formalism -- the contributions are reprinted in Benacerraf's anthology Philosophy of Mathematics. From Carnap's diary: "6-1/2 9 [6pm to 8:30pm] Cafe Reichsrat ... preparations for the trip to Königsberg. Gödel's discovery: incompleteness of the system of Principia Mathematica ... difficulties of the consistency proof."  In February 1930, Gödel and Tarski discussed logic here during the latter's first visit to Vienna.

The Reichsrat no longer exists, and the only picture that's around shows just the top of one of its doors (from Jimmy Schimanovich's photo gallery).

The window atop the door, columns, and stucco match the entrance to the Konditorei Sluka at Rathausplatz 8, and presumably on the basis of this it's long been believed that the Reichsrat used to be located where the Sluka is now. But the Sluka has been around since 1891, which led Paul Raymont to speculate that it expanded into the Reichsrat's space after the latter closed down. In 2010, Karlis Podnieks noticed that on the other side of the main driveway to Rathausplatz 8 there's another door that also looks like the one in the picture, and conjectured that the Reichsrat might have been located there. But Vienna's Kaffeehäuser were cavernous establishments and also almost all located at corners. So I asked Karl Sigmund, co-editor of Kurt Gödel: The Album and creator of the Gödel Exhibition, for help, and he suggested to check the phone book!  And indeed, Adolph Lehmann's allgemeiner Wohnungs-Anzeiger : nebst Handels- u. Gewerbe-Adressbuch für d. k.k. Reichshaupt- u. Residenzstadt Wien u. Umgebung gives the address for the Reichsrat as Stadiongasse 2.

Phone book entry for Kaffeehaus Reichsrat

The Café Reichsrat was thus located at the north-west corner of Stadiongasse and Reichsratsstraße/Rathauspark, and the archive picture probably shows the mid-block back entrance facing the Rathauspark identified by Podnieks. A bank now occupies the space:

Location of the former Café Reichsrat in Vienna

If you go visit, do have a coffee and cake at the Sluka!  I also made a map for all you Gödel pilgrims.

And here is some background reading:

John W. Dawson, Jr., Karl Sigmund, 2006. Gödel’s Vienna. The Mathematical Intelligencer 28(3), 44-55

For an almost complete list of people and places from the time of the Vienna Circle, consult:

Volker Thurm, 2003. Wien und der Wiener Kreis: Orte einer unvollendeten Moderne: Ein Begleitbuch, Vienna: facultas.wuv / maudric

Bleg: Philosophy survey for mathematicians

Submitted by Richard Zach on Mon, 07/21/2014 - 4:42am

A group of researchers in philosophy, psychology and mathematics are requesting the assistance of the mathematical community by participating in a survey about mathematicians’ philosophical intuitions. The survey is here: http://goo.gl/Gu5S4E. It would really help them if many mathematicians participated. Thanks.

The Place of Logic in Computer Science Education Followup

Submitted by Richard Zach on Thu, 07/17/2014 - 4:42am

The Special Session on "The Place of Logic in Computer Science Education" took place at the Logic Colloquium on Tuesday. It was well attended and, I think, overall a successful session.  The newly-formed ACM Special Interest Group on Logic and Computation (SIGLOG) was represented by its chair Prakash Panangaden.

Summer of Logic Dance Party

Submitted by Richard Zach on Sat, 07/12/2014 - 11:22am

So there will be a student party at the Summer of Logic. Help me crowdsource logic/math/CS/AI tracks, preferably danceable. Ideas?

Pet Shop Boys - He Dreamed of Machines

Turing Machines - Slave to the Algorithm

My Robot Friend - Robot High School

Joachim Lambek (1922-2014)

Submitted by Richard Zach on Sat, 06/28/2014 - 7:54am

More sad news, via the Studia Logica list:

We sadly inform that Professor Joachim Lambek (Jim for friends) passed away on June 23, 2014, at 2:00 p.m. in Montreal.

Getting Excited about the Computational Logic Olympics

Submitted by Richard Zach on Thu, 06/19/2014 - 11:19am

So while everyone is following the World Cup, I'm getting excited about the FLoC Olympic Games to be held at the Vienna Summer of Logic this year.  Still doing my research to pick favourites, but here are some of the disciplines:

plus a few others.  There will even be live viewing and a medal ceremony!

Grigori Mints, 1939-2014

Submitted by Richard Zach on Fri, 05/30/2014 - 5:46am

(C) George BergmanVery sad news today: Grisha Mints has died.  He was born June 7, 1939 in Leningrad (now St. Petersburg). He received his education in mathematics at Leningrad State University under N. A.

Simple Way to Document Code with Markdown, grep, and pandoc

Submitted by Richard Zach on Thu, 05/29/2014 - 2:26pm

Here's a simple way to pretty-print documentation included as comments in a source file (I'm mainly interested in LaTEX code), with or without the intervening code.  It's useful if you don't want to bother with a more complicated solution such as LaTeX's docstrip + ltxdoc.  It uses the ubiquitous bash tools grep and cut (available on Linux and probably (?) on Mac OS) plus John MacFarlane's pandoc , which you might have to install

SIGLOG Launches

Submitted by Richard Zach on Thu, 05/29/2014 - 12:36pm

Just came via the proof theory mailing list. I'm wondering why the ASL is not mentioned along with the EATCS, EACSL, and KGS.

Arthur Prior Centenary Conference, August 21-22, 2014

Submitted by Richard Zach on Thu, 05/29/2014 - 6:46am

The Arthur Prior Centenary Conference will be held at Balliol College, Oxford, on 21–22 August 2014, to celebrate the work of Arthur Norman Prior (1914-1969). Prior was a Fellow of Balliol and famous for his contributions to logic, ethics and metaphysics, but most of all he is known as the founder and principal inventor of modern symbolic temporal logic; for more details, see the conference website.

Ergo Publishes First Issue, Report

Submitted by Richard Zach on Tue, 05/27/2014 - 1:49pm

Ergo is a new general philosophy journal, open access, licensed under CC, with an innovative editorial model and triple-blind review.  Their first issue with four papers was published today, the papers are discussed on topic-appropriate blogs.

Read the report on submissions, turn-around times, etc., by the editors Jonathan Weisberg and Franz Huber here.

Post-doc in Groningen: The Roots of Deduction

Submitted by Richard Zach on Fri, 05/23/2014 - 11:47am

Within the VIDI project ‘The Roots of Deduction’ led by Catarina Dutilh Novaes, the Faculty of Philosophy of the University of Groningen is advertising a 12-month post-doc position, to commence in January 2015 or shortly thereafter.

Large Cardinal 2048

Submitted by Richard Zach on Sat, 05/17/2014 - 10:34am

Bored by small powers of 2? You can now play 2048, but with large cardinals instead. For the long version, you have to get all the way to 0=1.

Fork by Chris Le Sueur, h/t David Schrittesser

SEP Entry on Łukasiewicz

Submitted by Richard Zach on Thu, 05/15/2014 - 12:17pm

The Place of Logic in Computer Science Education

Submitted by Richard Zach on Wed, 05/07/2014 - 12:42pm

Helmut Veith and I are organizing a special session at the Logic Colloquium in Vienna.  The panelists will be Byron Cook (Microsoft Research), Alexander Leitsch (University of Technology Vienna), Prakash Panangaden (McGill University),

Did You Know Who Invented BASIC!?

Submitted by Richard Zach on Mon, 05/05/2014 - 7:28pm

John G. Kemeny and his daughterWow. Learn something new every day.

a) BASIC just turned 50 years old four days ago.

Anyone Got Good Frege Jokes? (Or Any Logic Jokes, Really?)

Submitted by Richard Zach on Mon, 05/05/2014 - 10:16am

Please add your favorite Frege joke in comments (or tweet @RrrichardZach with #fregejokes hashtag).

Doesn't have to be good. In fact, just any logic joke is fine.

Pages

Site Feed

Subscribe to Syndicate