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Re: ISSUE-126 (Revisit Datatypes): A proposal for resolution

From: Michael Smith <msmith@clarkparsia.com>
Date: Tue, 01 Jul 2008 12:22:19 -0400
To: Alan Ruttenberg <alanruttenberg@gmail.com>
Cc: Boris Motik <boris.motik@comlab.ox.ac.uk>, 'OWL Working Group WG' <public-owl-wg@w3.org>
Message-Id: <1214929339.26489.34.camel@msmith-laptop-wired.int.clarkparsia.com>

On Tue, 2008-07-01 at 11:13 -0400, Alan Ruttenberg wrote:

> Michael, could you give an example of what your concern was re:  
> internal representation of literals, and how it might play out?

My primary concern was that we were getting close to spec'ing
implementation details.  I agree with Boris that such details aren't
important.  My point was that tools might not care about structural
changes so we shouldn't assume a particular implementation.


However, since you asked, here's a trivial example - if a tool could
implement an internal representation based on value space identity
instead of lexical identity so that "1.0"^^xsd:decimal and
"1"^^xsd:decimal could share the same object / db row / etc.
 
For a large ABox with a large number of data property assertions, an
additional requirement to store the lexical value may impose a
significant memory burden.  On the other hand, not storing the canonical
(i.e., value space) identity (so it is computed on the fly, perhaps many
times) could make some activities much slower (consider DBMS style
indexing of a datatype for more efficient query).

That might mean my input data is "02.20"^^xsd:decimal but as a query
result "2.2"^^xsd:decimal  is returned.  I think that in some
applications trading that for reduced memory consumption and reasoning
runtime is permissible.

-- 
Mike Smith

Clark & Parsia
Received on Tuesday, 1 July 2008 16:24:24 UTC

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