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Fwd: comments on wording in AS&S

From: Jim Hendler <hendler@cs.umd.edu>
Date: Sat, 10 May 2003 23:15:36 -0400
Message-Id: <p05200f06bae36ea85edb@[10.0.1.2]>
To: Dan Connolly <connolly@w3.org>
Cc: phayes@ai.uwf.edu, Guus Schreiber <schreiber@cs.vu.nl>, Sandro Hawke <sandro@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>

Dan-
  I find myself with something that I as chair have no clue as to how 
to handle -- we now have an official comment criticizing one of our 
documents from someone listed as an editor of the document the 
comment is being raised against. I believe this can lead to some 
interesting logical paradoxes when applied literally to process - 
but let's at least note that it is very silly.
  So, I would like to suggest that Pat or I will send a reply to the 
public comments list which tags this as "[moved to www-webont-wg]" 
and then we handle it as an internal matter
  Does anyone have a problem with this solution?
  -JH


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From: pat hayes <phayes@ai.uwf.edu>
Subject: comments on wording in AS&S
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The relationships between OWL Full, OWL DL and OWL Lite could be 
brought into somewhat sharper focus by some changes to the wording in 
the document. I would suggest the following changes.

-----

1. Introduction, second para, remove needless judgemental prose and 
clarify the relationships more explicitly:

"This document contains two formal semantics for OWL. One of these, 
defined in Section 3 , is a direct model-theoretic semantics for the 
abstract syntax, which applies to OWL DL and OWL Lite. The other, 
defined in section 5, is a vocabulary extension of the RDFS semantics 
[RDF MT] which applies to OWL Full. The first semantics is simpler, 
but does not apply to cases which are excluded by the abstract 
syntax, such as where classes need to be treated as individuals. We 
show that the two semantics align naturally on the subset of OWL-RDF 
graphs which conform to the abstract syntax under the translation in 
section 4.
Appendix A...."

later:
"For such OWL ontologies the direct model theory is authoritative and 
the RDFS-compatible model theory is secondary. "
change to:
"We believe that for such OWL ontologies, the two semantic 
descriptions define the same entailments. In case any divergences are 
found, however, the direct semantics should be taken to be normative 
for OWL DL and OWL Lite ontologies."

Acknowledgements: DAM+OIL -> DAML+OIL
-----

Section 2., first sentence, following "and thus..": . Either omit, or 
expand on what is meant by "facilitates access to"

In general, throughout this section, "OWL" is used without 
qualification  to refer to OWL DL, which is potentially misleading to 
the reader, particularly in a separated document of this kind. I 
suggest replacing "OWL" with "OWL DL" throughout this section.

"(Note, however, that both ... and ... do not provide..." / "(Note, 
however, that neither ... or ... provide ... "

Similarly, references to what cannot be done in "an ontology" in 
section 2.1 should be clarified, eg  "A URI reference cannot be both 
a datatypeID and a classID in an ontology "/ "...in an OWL DL 
ontology".

This may require some extensive massaging of the text in section 2.1, 
which in any case contains many partial truths and unclear statements.

The usage of "class" and "set" in this section should be clarified 
and made rigorous. If this text is written under the assumption that 
class names denote sets, it would be helpful if this were stated 
clearly, preferably at the beginning of section 2, and an explicit 
contrast drawn with RDF/S. (I can provide anchors in [RDF MT] to a 
brief discussion of the issue if that would be helpful.)

"The class with identifier owl:Nothing is the empty class."
If 'class' here refers to the RDFS sense, there may be many empty 
classes. Suggest change to "an empty class", or "the empty set".

" In OWL, as in RDF, a datatype denotes the set of data values that 
is the value space for the datatype. Classes denote sets of 
individuals. "
This is not quite accurate. The datatype URIref in RDF denotes the 
datatype: the class extension is the set of data values. Also, 
classes do not denote.

"Ontology annotations that use owl:imports have the extra effect of 
importing the target ontology."   This does not explain what is meant 
by "importing". As it stands it conveys almost no information; a 
brief explanation would be useful.

The discussion of 'names' of an ontology should make no reference to 
the use of URIs in web access. The names of ontologies in the 
abstract syntax have no connection to any Web construct, as is made 
clear by the discussion of 'web-compatible' later in section 5.  An 
explicit statement to that effect would clarify this section, eg 
(suggestion only)

"The abstract syntax assumes that every ontology has a name. The 
obvious intended purpose of this is to provide a means to refer to, 
and hence access, a document containing a version of the ontology in 
some communicable syntax; but at this abstract level, the 
relationship between an ontology and its name is considered purely 
platonic. We will return to this matter when discussing OWL-RDF 
ontologies as entities which can be denoted by URIs. "

-----
Section 3, first paragraph, suggested rewrite:

"This semantics is a conventional model theory attached to the OWL 
abstract syntax, and therefore applies only to OWL DL and OWL Lite. 
It differs from the RDF semantics in several respects. It interprets 
class and property names extensionally, uses a nonstandard 
interpretation of rdf:type and differs slightly in its treatment of 
typed literals. The semantics for OWL Full in section 5 is more 
complicated, but is fully consistent with the RDFS semantics."

-----

Pat (Wearing no hats, for once.)

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-- 
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
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Received on Saturday, 10 May 2003 23:15:47 GMT

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