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Re: draft responses for LC comments JC1a and JC1b/34 et al

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 06 Mar 2009 16:24:56 -0500 (EST)
Message-Id: <20090306.162456.156422036.pfps@research.bell-labs.com>
To: ian.horrocks@comlab.ox.ac.uk
Cc: public-owl-wg@w3.org
I propose the following changes related to this issue.  (This depends on
the WG deciding to make decimal and float and double disjoint.)


If decimal, float, and double are disjoint, then owl:real can't contain
them all.  If it did, then it would contain "2"^^xsd:int,
"2"^^xsd:float, and "2"^^xsd:double, which would all be different.

Therefore, I would make owl:rational contain xsd:decimal (i.e., not
xsd:float or xsd:double) and owl:real contain owl:real (i.e., not
xsd:float or xsd:double).  I would also remove owl:realPlus, as there is
no longer a need for it.


The rationale for owl:rational remains the same, representing fractions
and results of the linear n-ary stuff.  The rationale for owl:real
then becomes representing arbitrary numeric values without dragging in
the problems associated with real and double.

peter


From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Subject: draft responses for LC comments JC1a and JC1b/34 et al 
Date: Fri, 6 Mar 2009 21:06:11 +0000

> I have finished working on these. I rolled in the comments coming out of
> the F2F discussions and made various other small improvements.
> 
> The only thing left to do is to complete the responses to the queries
> about datatypes at the end of JC1b. These is waiting for the decision on
> disjointness that we are going to make this coming Wednesday. It also
> isn't completely clear how to respond to the comments about owl:real:
> 
> owl:real
>     A possible motivation for owl:real is to allow a property which can be
>     used with any numeric datatype. TopQuadrant customers have such use
>     cases, when merging data from various sources: however, the use of a
>     simple XSD union datatype is an alternative solution, which we prefer.
> 
> owl:real
>     A possible motivation for use of owl:real is to permit integration of
>     numeric reasoning services in with ontological reasoning services. While
>     this may be useful for some Semantic Web application, we do not find
>     this to be useful for our business. We do find it critical that numbers
>     in semantic web applications interoperate with numbers in databases, and
>     with numbers in programming languages. We hence suspect that this
>     proposed change to the semantics of datatypes in OWL is a further
>     example of a clean theoretical solution that does not make practical
>     business sense. We suggest that the value spaces of the XSD datatypes
>     should remain unchanged from OWL1.
> 
> We could simply responding that it is useful to have a single numeric
> type that includes all the others and that the WG preferred owl:real to
> using an XSD union datatype.
> 
> Ian
Received on Friday, 6 March 2009 21:25:00 GMT

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