From pycyn@aol.com Thu Aug 09 17:43:00 2001 Return-Path: X-Sender: Pycyn@aol.com X-Apparently-To: lojban@yahoogroups.com Received: (EGP: mail-7_3_1); 10 Aug 2001 00:42:59 -0000 Received: (qmail 27579 invoked from network); 10 Aug 2001 00:42:58 -0000 Received: from unknown (10.1.10.142) by m8.onelist.org with QMQP; 10 Aug 2001 00:42:58 -0000 Received: from unknown (HELO imo-r08.mx.aol.com) (152.163.225.104) by mta3 with SMTP; 10 Aug 2001 00:42:58 -0000 Received: from Pycyn@aol.com by imo-r08.mx.aol.com (mail_out_v31.9.) id r.c5.1492208a (4068) for ; Thu, 9 Aug 2001 20:42:52 -0400 (EDT) Message-ID: Date: Thu, 9 Aug 2001 20:42:51 EDT Subject: Re: [lojban] A or B, depending on C, and related issues To: lojban@yahoogroups.com MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_c5.1492208a.28a4880b_boundary" X-Mailer: AOL 6.0 for Windows US sub 10531 From: pycyn@aol.com --part1_c5.1492208a.28a4880b_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/9/2001 6:24:35 PM Central Daylight Time, jjllambias@hotmail.com writes: > "if P then Q, else R," which are also pleasantly simple: > >(if P then Q) and (if not P then R)" and "(P iff Q) and (not P iff R)" > >While > >I am sure there are easier ways to show that these are the simplest forms > >for > >these functions, I confess to just having run all the possibilities from > >disjunctive normal forms on down. > > Neither of them is "Q or R, depending on P" though. One of > the versions of that would be: > > [(if P then Q) and (if not P then R)] xor > [(if not P then Q) and (if P then R)] > Well, they are in fact the two things that I usually see when I ask for an explanation of that phrase, and they do fit the requirements. I admit the other is more thorough sounding, but does it really introduce a new possibility in the concrete? Similarly, is the "P or Q, depending on the weather" more than an inspecific way to saying something of the first or second sort -- just failing to mention how the dependency goes. Since this all is out of the {makau} thread, which is about hiding significant information, perhaps that is an important fact, but then we need to see how these connections are going to work: (if Pkau then Q) and (if not-Pkau then R)? The best simplification I could find in a dash was ~(Q&R) &(P => QvR) , which, while shorter, is markedly less informative when talking about depndencies. --part1_c5.1492208a.28a4880b_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/9/2001 6:24:35 PM Central Daylight Time,
jjllambias@hotmail.com writes:


"if P then Q, else R," which are also pleasantly simple:
>(if P then Q) and (if not P then R)" and "(P iff Q) and (not P iff R)"  
>While
>I am sure there are easier ways to show that these are the simplest forms
>for
>these functions, I confess to just having run all the possibilities from
>disjunctive normal forms on down.

Neither of them is "Q or R, depending on P" though. One of
the versions of that would be:

[(if P then Q) and (if not P then R)] xor
[(if not P then Q) and (if P then R)]


Well, they are in fact the two things that I usually see when I ask for an
explanation of that phrase, and they do fit the requirements.  I admit the
other is more thorough sounding, but does it really introduce a new
possibility in the concrete?  Similarly, is the "P or Q, depending on the
weather" more than an inspecific way to saying something of the first or
second sort -- just failing to mention how the dependency goes.   Since this
all is out of the {makau} thread, which is about hiding significant
information, perhaps that is an important fact, but then we need to see how
these connections are going to work: (if Pkau then Q) and (if not-Pkau then
R)?

The best simplification I could find in a dash was ~(Q&R) &(P => QvR) ,
which, while shorter, is markedly less informative when talking about
depndencies. --part1_c5.1492208a.28a4880b_boundary--