Imaginary logic

Jeffery Wilson clueland.com · 18 Oct 2014, 23:49 · from 2014-October.txt.gz

This is the message as the crawl holds it, before anything here touched it. What the conversation shows has been through ingest: transfer encodings decoded, attachments dropped, quote markers repaired, and the archiver’s ? resolved into quotation marks and dashes. Those repairs are judgements and some of them are wrong, which is what this page is for. Email addresses are obscured here as they are everywhere else on the site, so it is before our repairs rather than byte for byte.

From: jwilson at clueland.com (Jeffery Wilson clueland.com)
Date: Sat, 18 Oct 2014 18:49:01 -0500
Subject: (urth) Imaginary logic
In-Reply-To: <ECB7FE8E-43B8-4702-8386-AEDF430F7927 at gmail.com>
References: <BAY172-W30F0FFD01111E474258437DFA80 at phx.gbl>	<CAJ8=rtim+RoC7jbpxGKFyJ0Pa976V-NEZYv8EuXK8K_ZWi_uNA at mail.gmail.com>
	<ECB7FE8E-43B8-4702-8386-AEDF430F7927 at gmail.com>
Message-ID: <5442FC6D.2020101 at clueland.com>

On 10/18/2014 2:18 PM, Ant?nio Pedro Marques wrote:
> Can someone more math-enjoying than me take up the challenge to build a
> system based on (A => B) & (A & ~B) ? Could some insight come out of the
> thing?

Well, rewriting A=>B as ~A V B gives

(~A V B) & (A & ~B)

which is not satisfiable because  the right group requires A to be true 
and B to be false, but the left requires either A to be false or B to be 
true. This expression is thus false for all possible combinations of 
values for A & B, so it can be used to imply anything, but since the 
proposition is always false, the consequent can be false or true without 
giving any useful information:

http://mathforum.org/library/drmath/view/55617.html

-- 
Jeff Wilson - < jwilson at clueland.com >
A&M Texarkana Computational Intelligence Lab
< http://www.tamut.edu/cil >

An unofficial mirror of a public mailing list · about & removal requests · download the archive · before the list · original archive at urth.net