From pycyn@aol.com Fri Aug 10 08:21:18 2001 Return-Path: X-Sender: Pycyn@aol.com X-Apparently-To: lojban@yahoogroups.com Received: (EGP: mail-7_3_1); 10 Aug 2001 15:21:18 -0000 Received: (qmail 85552 invoked from network); 10 Aug 2001 15:20:43 -0000 Received: from unknown (10.1.10.27) by l7.egroups.com with QMQP; 10 Aug 2001 15:20:43 -0000 Received: from unknown (HELO imo-m09.mx.aol.com) (64.12.136.164) by mta2 with SMTP; 10 Aug 2001 15:20:42 -0000 Received: from Pycyn@aol.com by imo-m09.mx.aol.com (mail_out_v31.9.) id r.a9.198893f2 (3982) for ; Fri, 10 Aug 2001 11:20:40 -0400 (EDT) Message-ID: Date: Fri, 10 Aug 2001 11:20:39 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_a9.198893f2.28a555c7_boundary" X-Mailer: AOL 6.0 for Windows US sub 10531 From: pycyn@aol.com X-Yahoo-Message-Num: 9393 --part1_a9.198893f2.28a555c7_boundary Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable In a message dated 8/9/2001 9:19:07 PM Central Daylight Time,=20 jjllambias@hotmail.com writes: > >The best simplification I could find in a dash was ~(Q&R) &(P =3D> QvR) = , > >which, while shorter, is markedly less informative when talking about > >depndencies. >=20 > Actually, that reduction fails when P, Q, and R are false. > (It gives true, should give false.) >=20 Yup! One problem with working at a dash when you have lousy handwriting=20 (never mind P anQ, it's T and F that are the problems). (Q xor R)> I would have taken the reduction as evidence that this was a totally=20 inappropriate rendition of "Q or R depending on P" since it says that Q or = R=20 regardless of P (or anything else). But then, I don't understand what all = of=20 this has to do with indirect questions exactly -- or with whatever keeps=20 being called indirect questions while being neither (unless "indirect" mean= s=20 "vague").=20=20 I suppose "{xn} depends on {ym}" means something like "there is a set of tr= ue=20 conditionals (not necessarily truth-functional, if that bothers people) who= se=20 antecedents are each a member of {ym} and whose consequents are members of= =20 {xn}" and then some details about completeness and exclusiveness -- which=20 might vary from case to case, as might the details of how the conditionals= =20 run. The vaguer terms ("what's for dinner," "what's in the icebox," "what= =20 the weather is") just cover these lack of details, while guaranteeing the=20 gneral (though possibly vacuous) claim. The only connection I can see between all this and questions is the=20 possibility that=20 expressions like "what's in the icebox" stands for a set of answers (claims= =20 in this case, not propositions).=20=20 --part1_a9.198893f2.28a555c7_boundary Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable In a message dated 8/9/2001 9:19:07 PM Central Daylight Time,=20
jjllambias@hotmail.com writes:


>The best simplificati= on I could find in a dash was ~(Q&R) &(P =3D> QvR) ,
>which, while shorter, is markedly less informative when talking abo= ut
>depndencies.

Actually, that reduction fails when P, Q, and R are false.
(It gives true, should give false.)

Yup!  One problem with working at a dash when you have lousy handw= riting=20
(never mind P anQ, it's T and F that are the problems).

<The actual reduction, funnily enough, turns out to be (Q xor R),
independent of P!

What's more, this other one:

[(P iff Q) and (not P iff R)] xor [(not P iff Q) and (P iff R)]

also reduces to the same thing: (Q xor R).

This makes sense, because the truth value of "Q or R depending on P"
cannot depend on the truth value of P, since we are not specifying
what the dependency is. This fits in very nicely with the Pkau
interpretation, which might be:

=A0=A0 Pkau =3D> (Q xor R)>

I would have taken the reduction as evidence that this was a totally=20
inappropriate rendition of "Q or R depending on P" since it says that Q= or R=20
regardless of P (or anything else).  But then, I don't understand = what all of=20
this has to do with indirect questions exactly -- or with whatever keep= s=20
being called indirect questions while being neither (unless "indirect" = means=20
"vague").  

I suppose "{xn} depends on {ym}" means something like "there is a set o= f true=20
conditionals (not necessarily truth-functional, if that bothers people)= whose=20
antecedents are each a member of {ym} and whose consequents are members= of=20
{xn}" and then some details about completeness and exclusiveness -- whi= ch=20
might vary from case to case, as might the details of how the condition= als=20
run.  The vaguer terms ("what's for dinner," "what's in the icebox= ," "what=20
the weather is") just cover these lack of details, while guaranteeing t= he=20
gneral (though possibly vacuous) claim.
The only connection I can see between all this and questions is the=20
possibility that=20
expressions like "what's in the icebox" stands for a set of answers (cl= aims=20
in this case, not propositions).   --part1_a9.198893f2.28a555c7_boundary--