[Jdrew-all] Questions regarding RuleML status

[Boley, Harold]

Hi Bart and All,

I go through your questions below, Ccing in the RuleML list.
Future emails should go to either of these lists separately,
depending on whether they are more about the language RuleML
or about (OO) jDREW as one of its implementations.

Best,
Harold



Concerning RuleML itself:

* how are rule labels defined, and what does this look like in the POSL
counterpart?

We had these http://www.ruleml.org/0.88/#Changes in an earlier version:

Affecting the semantics, 'rbaselab' and 'rlab' are unified into 'oid',
which is also used for general object identification. For example,

<Atom>
  <oid><Ind>gpKR fact 1</Ind></oid>
  <opr><Rel>offer</Rel></opr>
  <Ind>Ecobile</Ind>
  <Ind>special</Ind>
  <Ind>20000</Ind>
</Atom>

But I now think 'oid' should be reserved for object identification,
and rule/rulebase/... labeling should be done with existing XML means
(id/idref, XPointer), although labels must be simply strings then.

Thus, the above example could use "gpKR fact 1" as the value of id
(also note RuleML 0.9's <op>):

<Atom id="gpKR fact 1">
  <op><Rel>offer</Rel></op>
  <Ind>Ecobile</Ind>
  <Ind>special</Ind>
  <Ind>20000</Ind>
</Atom>

POSL, while allowing object identification (anchoring), currently
doesn't have a convention for rule labels. We could see if the
convention of SWSL-Rules (http://www.daml.org/services/swsf esp.
http://www.daml.org/services/swsf/1.1/swsl/#swsl-rules-courteous)
or of another human-oriented syntax is the best one to adapt.


* is modality supported, if so which ones and how? (like modal logic,
deontic logic, temporal logic)

Not officially yet, except if you count integrity constraints,
which RuleML 0.9's <Protect> allow us to express. However, newer
work in Functional RuleML (http://www.ruleml.org/fun) suggests
to introduce an attribute in(terpreted) inside <Fun>, e.g.
<Fun in="no"> for uninterpreted function symbols, so far written as
<Ctor>. Using the same attribute inside <Rel> permits to introduce
uninterpreted relation symbols <Rel in="no">, not available before.
These can be used inside the "opaque contexts" created by modal
operators such as 'believes':

<Atom>
  <op><Rel>believes</Rel></op>
  <Ind>John</Ind>
  <Atom>
    <op><Rel in="no">made of</Rel></op>
    <Ind>moon</Ind>
    <Ind>cheese</Ind>
  </Atom>
</Atom>


* how are quantifiers expressed in POSL?

Prolog's implicit variable quantification is assumed in Horn POSL.
There is no FOL POSL yet. We could look into this.



Concerning Policy RuleML:

* has anything been happening in that regard, like an inital policy
language?

Said Tabet has renewed interest in this, esp. in compliance policies.
Watch out for a possible compliance session of the Business Rules Forum
(http://www.businessrulesforum.com) or its European counterpart.



Concerning OO jDREW:

* does the engine support strong negation already, i.e. 'Not'? and what
about 'Naf'

SianLun gave a good answer here.

* are priority statements of the type 'overrides' already supported?

Not in (OO) jDREW. We could benefit from the SweetRules system here
(http://sweetrules.projects.semwebcentral.org).

* related to that, can rules be labelled already in OO jDREW?

Only a form of object identification (anchoring), not rule labeling,
is supported in OO jDREW so far. We hope to soon update this:
http://mail.jdrew.org/pipermail/jdrew-all/2005-June/000001.html



-----Original Message-----
From: jdrew-all-bounces at jdrew.org [mailto:jdrew-all-bounces at jdrew.org]
On Behalf Of Bart Orriens
Sent: April 4, 2006 5:53 AM
To: jdrew-all at jdrew.org
Subject: [Jdrew-all] Questions regarding RuleML status


Hello everyone,

I have a couple of questions concerning the status of RuleML as it
stands right now. Hopefully you can provide me with (some of) the
answers. The questions I have are the following:

Concerning RuleML itself:

* how are rule labels defined, and what does this look like in the POSL
counterpart?
* is modality supported, if so which ones and how? (like modal logic,
deontic logic, temporal logic)
* how are quantifiers expressed in POSL? 

Concerning OO jDREW:

* does the engine support strong negation already, i.e. 'Not'? and what
about 'Naf'
* are priority statements of the type 'overrides' already supported?
* related to that, can rules be labelled already in OO jDREW?

Concerning Policy RuleML:

* has anything been happening in that regard, like an inital policy
language?

I would be much obliged if you could answer one or more of these
questions.

Kind regards,
Bart Orriens
=======================================
Drs. Bart Orriens          
B704, Tilburg University 	
PO Box 90153, 5000 LE Tilburg, 	 
The Netherlands
Phone : +31 13 4662779 
Fax   : +31 13 4663069                 
Email : b.orriens at uvt.nl
Web   : http://infolab.uvt.nl/~borriens   
=======================================
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