- From: Gerd Wagner <wagnerg@tu-cottbus.de>
- Date: Sun, 26 Nov 2006 23:27:22 +0100
- To: 'Hassan Aït-Kaci' <hak@ilog.com>
- Cc: "'RIF WG'" <public-rif-wg@w3.org>
> The contents of the slides written and shown by Harold are only meant
> as illustration. The concrete syntax of slotted term he added to the
> "core" condition and Horn rule language syntax is not formally consistent
The treatment of slots in this document, as it stands, is both
inconsistent and strange.
It's inconsistent because in the SYNTAX section, slots are defined
to be NAME-TERM pairs to occur as arguments of relations:
Rel '{' (NAME '->' TERM)* '}'
while in the markup example the slot name is marked up as
an individual constant as in
<Atom>
<Rel>purchase</Rel>
<slot><Con>buyer</Con><Var>Buyer</Var></slot>
<slot><Con>seller</Con><Var>Seller</Var></slot>
...
</Atom>
It's strange because slots correspond to property-value pairs, so
slot names correspond to property names which represent a special
(important) case of binary predicates (as in RDF and OWL).
Consequently, Harold's "slotted atom" should be replaced with
an expression that corresponds directly to F-Logic molecules
and to OWL individual descriptions:
TERM ':' Rel '{' (Rel '->' TERM)* '}'
where the first occurrence of Rel must be a unary (class)
relation, and the following occurrences of Rel must be
binary (property) relations. Of course, this would be
better defined on the basis of a vocabulary definition
language that does not just contain a single category for
predicates (Rel), but at least three such categoris (Class,
Property and Rel).
-Gerd
Received on Sunday, 26 November 2006 22:27:31 UTC