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Re: ISSUE-126 (Revisit Datatypes): A new proposal for the real <-> float <-> double conundrum

From: Richard H. McCullough <rhm@PioneerCA.com>
Date: Mon, 7 Jul 2008 19:16:57 -0700
Message-ID: <C109A82695B44252AB716AA3292F3081@rhmlaptop>
To: <paul@sparrow-hawk.org>, "Alan Ruttenberg" <alanruttenberg@gmail.com>, "Dave Peterson" <davep@iit.edu>
Cc: "Rob Shearer" <rob.shearer@comlab.ox.ac.uk>, <public-webont-comments@w3.org>, <public-owl-wg@w3.org>, <www-xml-schema-comments@w3.org>

I'm suggesting two things.
1. epsilon-delta arguments are applicable to determining how many numbers 
you can distinguish.
2. once that number gets sufficiently large, there's no point in considering 
the larger
number of "theoretical" answers, because you can't measure them, so they 
just don't matter.


----- Original Message ----- 
From: "Dave Peterson" <davep@iit.edu>
To: "Richard H. McCullough" <rhm@pioneerca.com>; <paul@sparrow-hawk.org>; 
"Alan Ruttenberg" <alanruttenberg@gmail.com>
Cc: "Rob Shearer" <rob.shearer@comlab.ox.ac.uk>; 
<public-webont-comments@w3.org>; <public-owl-wg@w3.org>; 
Sent: Monday, July 07, 2008 6:38 PM
Subject: Re: ISSUE-126 (Revisit Datatypes): A new proposal for the real <-> 
float <-> double conundrum

> Let me put one thing to bed once and for all:  No one that I'm aware of
> believes that (*absent artificial "coloring" for distinction*) the value
> space of float is not a subset of the value space of double, or that
> the value space of double is not a subset of the value space of decimal.
> The problem is in the details of all the additional baggage a datatype
> carries, over and above its value space.
> At 4:38 PM -0700 2008-07-07, Richard H. McCullough wrote:
>>I suggest that you consider following the example of classical 
>>mathematical analysis -- the delta-epsilon arguments -- or the example of 
>>engineering approximations.
> I'm very interested in knowing how Leibnizian epsilon-delta arguments
> impact the question of how one can or should derive double, and then
> float, from decimal.
>>Domains may be disjoint in theory, but when you make real measurements,
>>and consider measurement precision/errors, they're not really disjoint.
> True.  But there's a lot of difference between saying you have "numbers"
> whose exact value you don't know (a la precisionDecimal) and saying that
> you have a fixed finite set of numbers into which you must jam all your
> values.  Some of the Schema WG members won't even talk to me about
> precision any more because I get into too much detail as to just what
> precision is in engineering measurement contexts.  Best don't get me
> started.  ;-)
> -- 
> Dave Peterson
> SGMLWorks!
> davep@iit.edu
Dick McCullough
Ayn Rand do speak od mKR done;
knowledge := man do identify od existent done;
knowledge haspart proposition list;
mKE do enhance od "Real Intelligence" done;
Received on Tuesday, 8 July 2008 02:22:32 UTC

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