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

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Fri, 4 Jul 2008 17:25:14 +0100
Message-Id: <3463F385-B480-4147-AAF0-8EEFE6CF47E1@cs.man.ac.uk>
To: OWL Working Group WG <public-owl-wg@w3.org>

On 4 Jul 2008, at 16:09, Alan Ruttenberg wrote:

> On Jul 4, 2008, at 11:07 AM, Bijan Parsia wrote:
>
>> Because the floats are lexicographically ordered that means that  
>> if we increment the representation of a float as an integer then  
>> we move to the next float....
>
> Not if the next one is NaN.

NaN isn't in the sequence. In particular, I believe that all  
comparisons with NaNs are false (including equality). Thus the  
datatype >NaN is *necessarily* empty. As is =NaN, actually. To test  
for NaNness, you need a special predicate.

> Not every bit sequence in the floats corresponds to a number.

The sequences representing numbers do, and they are lexicographically  
ordered. You don't need to consider NaN when computing interval sizes.

Cheers,
Bijan.
Received on Friday, 4 July 2008 16:22:59 UTC

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