From rlpowell@digitalkingdom.org Mon Apr 30 11:45:38 2001 Return-Path: X-Sender: rlpowell@digitalkingdom.org X-Apparently-To: lojban@onelist.com Received: (EGP: mail-7_1_2); 30 Apr 2001 18:45:38 -0000 Received: (qmail 79524 invoked from network); 30 Apr 2001 18:45:37 -0000 Received: from unknown (10.1.10.142) by m8.onelist.org with QMQP; 30 Apr 2001 18:45:37 -0000 Received: from unknown (HELO chain.digitalkingdom.org) (64.169.75.101) by mta3 with SMTP; 30 Apr 2001 18:45:35 -0000 Received: from rlpowell by chain.digitalkingdom.org with local (Exim 3.22 #1 (Debian)) id 14uIfh-0006y1-00 for ; Mon, 30 Apr 2001 11:45:21 -0700 Date: Mon, 30 Apr 2001 11:45:21 -0700 To: lojban@yahoogroups.com Subject: Predicate logic and childhood. Message-ID: <20010430114521.C20818@digitalkingdom.org> Mail-Followup-To: lojban@onelist.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.3.17i From: Robin Lee Powell X-Yahoo-Message-Num: 6993 So, having thought about this more, and remembering that the connectives in lojban are based on predicate logic, and that I know how to do that, here's some more on logical connective usage. Take the sentence: ko ca gasnu le nu le do kumfa ku cnici Call that sentence C. C is true iff, at a time that is more-or-less 'now', the child in the agentive cause of eir room becoming tidy. Next, we have: mi ba curmi le nu do klama le panka Call that sentence P. P is true iff, at a time that is more-or-less in the future, the parent gives the child permission to go to the park. I take it as obvious that P implies that such permission is not currently given (or there would be no ba tag). Take: C .inaja P Or, alternatively: If C then P using standard predicate logic meaning of 'If ... then ...'. Then we have the standard 4 cases: The child cleans eir room. Afterwards, the parent gives the child permission to go to the park. Clearly, with P and C both true, C -> P is true. The child cleans eir room. Afterwards, the parent does not give the child permission to go to the park. C -> P is false, ergo the parent lied (stated a false predication; what else could lying be in a logical language?). The child does not clean eir room. C is false, C -> P is therefore always true. This is actually really useful, because at this point _anything_ follows, including the parent giving the child a whuppin'. 8) However, for maximum clarity it would perhaps be best to use C .ijo P so that if the child does not clean eir room, and the parent allows the child to go to the park, the parent has lied again. Which the parent will probably reluctant to do, so this helps constrain the parent to not change eir mind. -Robin -- http://www.digitalkingdom.org/~rlpowell/ BTW, I'm male, honest. le datni cu djica le nu zifre .iku'i .oi le so'e datni cu to'e te pilno je xlali -- RLP http://www.lojban.org/