RE: Implementing OWL2-RL with a RETE rule engine.

Hi Olivier!

Two points:

1) It has already been mentioned that there may be some trouble with
implementing the rules for OWL constructs that use argument lists, such as
the rule for owl:unionOf:

    <http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#cls-uni>

You may have a look into the RIF OWL 2 RL document, which presents an
implementation of OWL 2 RL in RIF, and which discusses the issue of
implementing the "List rules" in quite some detail:

    <http://www.w3.org/2005/rules/wiki/OWLRL#List_rules>

Although it's RIF, some of the ideas given there may be helpful for your own
work.

2) There is a second significant implementation issue, which is the
implementation of the datatype/datavalue rules in Table 8 of the OWL 2 RL
spec:

    <http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#dt-type1>

For these rules, you will need to realize some specific datatype reasoning.
For example, you somehow need to be able to determine whether two given
literals denote the same data values, in order to correctly implement the
rule at

    <http://www.w3.org/TR/2009/REC-owl2-profiles-20091027/#dt-eq>   

For example, the literals "42"^^xsd:integer, "042"^^xsd:integer, and
"42.0"^^xsd:decimal are mutually different as literals, but denote all the
same datavalue: the number 42. Your reasoner must somehow be able to find
out that the values are in fact identical. With a simple rule engine, you
will probably not be able to implement this in terms of rules only, but need
some additional code for the datatype reasoning. You need to check whether
cwm has some sort of datatype reasoning support and whether it can be used
for this purpose.

Michael

Olivier Rossel wrote on Mon, 19 Apr 2010:
>As far as I understand, OWL2-RL is a subset of OWL2 that can be implemented
with a regular rules engines such as Jess, Drools or (may be) cwm.
>
>Is there a reference list of all the rules to be implemented by a rules
engine to be fully compliant with RL?
>Or, even better, a reference implementation of OWL2-RL for an existing
rules engine?

--
Dipl.-Inform. Michael Schneider
Research Scientist, Information Process Engineering (IPE)
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Received on Wednesday, 21 April 2010 20:15:37 UTC