% notes from JC telecon 6/24/03
% by Benjamin Grosof  

o rule test cases:

Mike has a bunch of wish cases, e.g., about equivalence
e.g., using sameIndividualAs or cardinality-1

he's working on an engine that has some knowledge of OWL, and uses N3 syntax,
that can do some of the rule test cases

todo:  talk with Mike about integrating his ideas/prototype with the 
SweetOnto/KAON work on DLP (Description Logic Programs) which was demo'd
by Boris Motik at WWW-2003 semantic web developers day

Benj:  wrt style:  suggestion:  more prose comments, 
organize by point made, e.g., domesticflight-1.n3 and uncle-1.n3
and siblingfather-1.n3 all give examples of ontological knowledge
that are hard/impossible to express in OWL-DL

"<>" denotes the current KB 

discussion about whether 
equality should be treated explicitly, and defined
by rules,  
vs. built into the language/engine

Benj:  we obviously want the capability for the latter,
but recommend the former as one available compliance level in the beginning,
for flexibility, since
many practical rule systems do not have it built in already with the full
strength of FOL semantics

Mike: this issue is very related to whether our requirement for the rule
language is 
to extend OWL
vs. 
to work optionally with OWL 

Mike's approach builds in knowledge of OWL to the rule language and system

Benj:  let's list this as an objective

Benj:  SweetOnto/KAON implementation that we have right now first translates
OWL/DL stuff into LP, then does inferencing in an LP rule system;
but it's nice to have the OWL syntax (say, for DLP expressive subset)
supported 

Benj during discussion with Pat:  
nonmon about equality, say default distinctness via NAF, 
is not well studied in the KR literature, 
so it would be more cautious (wrt sticking to what's already
well understood) to define equality as an ordinary
predicate and then explicitly axiomatize its substitutivity, transitivity,
symmetry

Pat:  but can't we rely on NAF as a mechanism to define nonmon aspects
of equality?

Benj:  yes, that's the direction I would take 

Benj:  wrt more test cases beyond DLP:
- for ontological knowledge, e.g., in MIT Process Handbook or 
various frame-based systems, often want nonmonotonic inheritance, thus 
beyond DLP
- it's pretty easy to give examples of cardinality or disjunction or 
existentials that go expressively beyond the current version of DLP

Pat in discussion with Mike and Benj:  
let's aim to have some OWL syntax directly within the rule language
Benj:  yes, this is a large motivation of the DLP work, 
but this might be beyond our V1 because it involves more complexity 

consensus:  yes; need RDF syntax for the rule language, and a corresponding
human presentation syntax e.g. cf. N3

Pat:  wrt syntaxes, let's look at TRIPLE by Stefan Decker and Michael Sintek