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Re: Web Rule Language - WRL vs SWRL

From: Sandro Hawke <sandro@w3.org>
Date: Fri, 01 Jul 2005 00:33:17 -0400
To: www-rdf-rules@w3.org
Message-Id: <20050701043321.BB7FE4EFB0@homer.w3.org>


Drew writes:
> Here's the nub: We are in the presence of an unfortunate pun.  All of
> these different "semantics" for LP concern the meaning of logic
> programs _as programs_.  But for interoperability what we care about
> is the semantics of logical expressions as _statements_. 

For my own sanity, I'm trying to stay focussed on test cases.  For RDF
and OWL we had, for instance, PositiveEntailmentTests (PETs) and
NegativeEntailmentTests (NETs), along with several other kinds of
tests.   Ideally, the tests correspond to how people are actually
going to use the language, and fit directly into a Conformance part of
the language specification.

The DAWG has Query Tests, which might work well for rules work.  For
DAWG they say "The dataset gives the exact graph against which the
query is evaluated (no further inference is used to determine the
input graph)" [1]. For a rule language version, I imagine reversing that
parenthetical to say something like "all licensed inference is done,
as necessary, to produce query results."   The test case might be
parameterized (as OWL tests were) by which language
profile/semantics/species applied.

Working through a SPARQL interface probably covers the space of RDF
rules pretty well; it's less clear whether and how more expressive
queries should be addressed in test cases.... and I understand that
fuzziness is helping fuel the Michael/Ian loop.   Ian?  Maybe you can
propose a concrete test case which demonstrates the difference in
semantics here?   Can you do it through a SPARQL query?   [Sorry if I
missed it earlier in the thread; I'm still catching up.]

      -- sandro

[1] http://www.w3.org/2001/sw/DataAccess/tests/README.html
Received on Friday, 1 July 2005 04:33:24 GMT

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