About medial

Alessio Guglielmi <Alessio.Guglielmi-r/[email protected]> Mon, 12 Apr 2004 10:55:27 +0200

Newsgroups	gmane.science.mathematics.frogs
Message-ID	<p06100500bca00565d8b0@[62.227.184.79]>

Hello,

the rule we call medial corresponds, in classical logic, to the tautology

    ((A ^ B) V (C ^ D)) -> ((A V C) ^ (B V D)) .

I've just seen (in Japaridze) a reference to this formula as Blass's 
principle. The formula in fact appears in the paper

    A game semantics for linear logic
    Andreas Blass
    Annals of Pure and Applied Logic 56 (1992) 183-220

which is available on Groucho.

I don't know more. Ciao,

-Alessio