Return-Path: Received: by snark.thyrsus.com (/\==/\ Smail3.1.21.1 #21.19) id ; Tue, 24 Mar 92 21:07 EST Received: by cbmvax.cbm.commodore.com (5.57/UUCP-Project/Commodore 2/8/91) id AA13451; Tue, 24 Mar 92 20:59:38 EST Received: from pucc.Princeton.EDU by relay1.UU.NET with SMTP (5.61/UUNET-internet-primary) id AA06443; Tue, 24 Mar 92 18:51:42 -0500 Message-Id: <9203242351.AA06443@relay1.UU.NET> Received: from PUCC.PRINCETON.EDU by pucc.Princeton.EDU (IBM VM SMTP V2R2) with BSMTP id 4804; Tue, 24 Mar 92 18:50:46 EST Received: by PUCC (Mailer R2.08 ptf012) id 8608; Tue, 24 Mar 92 18:50:35 EST Date: Tue, 24 Mar 1992 22:37:28 GMT Reply-To: Ivan A Derzhanski Sender: Lojban list From: Ivan A Derzhanski Subject: A pair of how-do-i-say-it's To: John Cowan , Eric Raymond , Eric Tiedemann In-Reply-To: Chris Handley's message of Wed, 25 Mar 1992 10:05:20 GMT+1200 <5715.9203242203@cogsci.ed.ac.uk> Status: RO X-From-Space-Date: Tue Mar 24 21:07:06 1992 X-From-Space-Address: cbmvax!uunet!CUVMA.BITNET!LOJBAN > Date: Wed, 25 Mar 1992 10:05:20 GMT+1200 > From: Chris Handley > > >Facts: > > > > president( GB, US) = true prime_minister( GB, US) = false > > president( JM, UK) = false prime_minister( JM, UK) = true > > Correct, but "leader"(GB, US) = true (in some sense) and > "leader"(JM, UK) = true (in a somewhat different sense) Why "but"? I was objecting against the universal quantification. `forall bu'a [GB bu'a US -> JM bu'a UK]': incorrect (you can think of a kajillion of counterexamples). `exists bu'a [GB bu'a US /\ JM bu'a UK]': correct but uninformative (you can think of a kajillion of trivial and irrelevant examples). What you want is something like `there is a bu'a, such that GB bu'a US and JM bu'a UK, but it is not a trivial one... no... guess again...' and the answer to the riddle is `lambda (x,y) [x is leader of y]'. Afraid you can't put this into logic, though. Ivan