Another logic/language/philosophy of math blog started up yesterday: languageandlogic.net. It’s still anonymous, but the author wrote over at consequently.org that she’ll put up contact details soon. One of the first posts discusses the fact that natural deductions for ordinary propositional logic normalizes (well, at least without negation it does), but it doesn’t when you add the intro and elim rules for Prior’s tonk.
Dear Richard,First of all, I would like to take this opportunity to tell you that I have been a passive reader for some time now and I really enjoy your Blog. I wanted to refer all people who are interested in Prior’s Tonk to a relevant paper by A. Avron and I. Lev, where they explain the problem of Tonk using the tool of Non-deterministic Matrices. Here is the link:http://antares.math.tau.ac.il/~aa/articles/nmatrices.pdf Posted by Anna Zamansky
I would not have seen this page, or the commentary at Brian Weatherson’s weblog , so hat tip.I posted a comment at Brian Weatherson’s page, basically pointing out that local reduction is a strictly weaker concept than what Michael Dummett calls local harmony. I’ve started a page on harmony at Greg Restall’s consequently.org wiki Posted by Charles Stewart