Message-Id: <199602092038.WAA05822@xiron.pc.helsinki.fi>
Date:         Fri, 9 Feb 1996 20:24:02 +0000
Reply-To: ucleaar <ucleaar@UCL.AC.UK>
Sender: Lojban list <LOJBAN@CUVMB.BITNET>
From: ucleaar <ucleaar@UCL.AC.UK>
Subject:      Re: TECH: fuzzy logic proposals (NEW CMAVO)
To: Veijo Vilva <veion@XIRON.PC.HELSINKI.FI>
Content-Length: 3035
Lines: 66

> I am now proposing the addition of two conventions for handling fuzzy
> logic:
> 1) for fuzzy truth statements, a convention that "je'a xi <number>"
> reflects the degree of truth of the statement in which it is embedded,
> thus:
> 1)      mi je'a xi pinomu blanu
>         I am (5%-true) blue.
> This is distinct from saying I have a 5% probability of being blue;
> probability does not enter into it.  A die has a 1/6 probability of
> coming up deuce, but it does so with a degree of truth that is 1 (with
> 1/6 probability) or 0 (with 5/6 probability): not fuzzy at all.  I had
> previously proposed this convention.

A. I haven't checked my records, which are a mess, but my recollection is
that you actually proposed a slightly different convention that applies
to ***{jaa}*** rather than {jea}. But I thought we needed a fuzzy NAE
as well as a fuzzy NA, so extrapolated (1).

B. I assume you'd go along with both {jea xi} and {jaa xi} (corresponding
to {xio} and {xoi} respectively). They differ importantly:

> Claims using this convention can be rewritten to use "jei" thus:
>        da je'a xi <number> broda = le jei da broda du li <number>

NO!! A ball can be at the same time both red and nonred, xunre and
nae xunre. The ball is both {jea xi 1 xunre} and {jea xi 0 xunre}.
But even though the ball is {jea xi 0 xunre}, the truth value of
{le bolci cu xunre} is 1 rather than 0 (- because the ball is also
{jea xi 1 xunre}).
To say, "it is 5% true that the ball is red", use:
   le bolci **jaa** xi .05 cu xunre
   = le jei le bolci cu xunre kei du li 0.5

C. Either {jea/jaa} get bleached of meaning when they have a xi subscript,
in which case Djer is right that this is uglily idiomatic, or you redefine
{jaa} as "it is some % true that" and {jea} as "is to some degree a ..."
with a default rule that if there is no {xi} then it is interpreted as if a
{xi 1.0} were present. I much prefer the latter approach.

D. I'd like to know how to say "jea xi very" and "jea xi slightly".
(A problem not resolved for the {xio}/{xoi} proposal.)

E. If A-D are resolved, then I might as well withdraw the {xoi}-{xio}
proposals (since the new proposals are a slightly clunkier version of
xoi/xio).

F. My related proposals for NA + CAI and NAE + CAI still stand, for
want of adequate alternative locutions. [They still stand in the sense
that I still think they're a good idea, but not in the sense that
I am requesting a real-world grammar change and concommitant refgrammar
revisions.]

G. Finally, note that Steven's insistence paid off.

> 2) for scalar claims generally, a new cmavo of selma'o MOI (for
> discussion purposes, "fiu'i"), with tentative place structure:
>        x1 is at <number> location on scale x2 (of type x3?)
> I'm not sure if x3 is useful; it is meant to be filled with things like
> "cardinal", "interval", etc.
> Comments?

This would be good for things Steven wanted.
It's a nice useful cmavo, so I'm in favour, but I note that we don't
actually NEED it; a lujvo would do equally well.

coo, mie And