W3C home > Mailing lists > Public > public-owl-wg@w3.org > January 2008

A comment on the Primer draft, part 1 Introduction

From: Ivan Herman <ivan@w3.org>
Date: Wed, 23 Jan 2008 11:11:19 +0100
Message-ID: <479712C7.1020704@w3.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: OWL Working Group WG <public-owl-wg@w3.org>
Bijan, Peter,

a small comment on

http://webont.org/owl/documents/primer.html

The current document says:

[[[
Resource Description Framework (RDF) and Schema: Of the technologies 
discussed in this section, RDF(S) is the closest to OWL. They both have 
roots in logic based knowledge representation; in many ways, RDF(S) can 
be seen as a subset of OWL; and, perhaps most prominently, the primary 
exchange syntax for OWL has been RDF/XML. However, there are differences 
of style, emphasis, and common practice that can make relying on RDF(S) 
intuitions misleading when working with OWL. For example, while OWL 
statements and expressions can be encoded as RDF facts (triples), the 
triple view is not typically a fruitful way of writing or understanding 
complex expressions. Similarly, it is fairly common and effective to 
work with RDF as a graph data structure or database where the primary 
focus is on the explicit statements in the graph. Even when we consider 
parts of RDFS which support implicit knowledge, such as subclass 
inheritance, the relation between the explicit and implicit statements 
is very direct. Thus, it is easy to conceptualize inference in terms of 
graph structure manipulation.

In contrast, OWL allows for -- and encourages -- operations that are not 
rooted so directly in the evident structure of an ontology.
]]]

I am not sure how to reconcile this paragraph with our constituency 
using RDFS plus one of the very simple fragments of OWL1.1 (say, DLP). 
For those users the last sentence may not be really true; their modus of 
operation is certainly using RDFS, explicit graph structure, triplets, 
and direct structure statements (eg, stating that a specific FOAF 
property is inverse functional in defining FOAF).

I know there is an open issue somewhere down in the document on how to 
address fragments in general, and I am not sure what your thoughts on 
that issue is. But we should avoid creating a possible misunderstanding 
in an introductory paragraph...

It may be as simple as saying that in the case of more complex 
ontologies "OWL allows for -- and encourages --" etc. I am not 100% sure 
either.

Ivan

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf


Received on Wednesday, 23 January 2008 10:11:30 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Wednesday, 23 January 2008 10:11:31 GMT