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Re: AS & S review: Direct model-theoretic semantics

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 17 Jan 2003 11:34:38 -0500 (EST)
Message-Id: <20030117.113438.72310435.pfps@research.bell-labs.com>
To: herman.ter.horst@philips.com
Cc: www-webont-wg@w3.org

From: herman.ter.horst@philips.com
Subject: AS & S review: Direct model-theoretic semantics
Date: Tue, 14 Jan 2003 17:42:03 +0100

> AS & S Section 3 Direct model-theoretic semantics
> Review comments
> The semantics of minCardinality and maxCardinality should 
> in fact be interchanged.

Good catch!  Thanks.

> First sentences in Section 3.1:
> "The semantics here starts with the notion of a vocabulary, 
> which can be thought of as the URI references that are of 
> interest in an OWL ontology. 
> It is, however, not necessary that a vocabulary consist only 
> of the URI references in an OWL ontology."
> - Here the first sentence is vague and should be more specific.
> What does "of interest" mean? Replace by something like: 
>    a vocabulary is a set of URI references including those 
>    appearing in a given OWL ontology.
> - Make the second sentence more specific: what else could it be?

Changed to:

The semantics here starts with the notion of a vocabulary, which is a set
of URI references.
When considering an OWL ontology, the vocabulary must include all the URI
references in that ontology, as well as ontologies that are 
<a href="owl_imports_closure">imported</a> by the ontology, but can include
other URI references as well. 

> Next sentence: there should be the word   and 
> between owl:Thing and owl:Nothing

Fixed already.

> The second line about Individual(...) in the table of 
> Section 3.2 requires a subscript 1 with c in EC(c).

Good catch.  Thanks.

> In the same table: the two lines on oneOf could use explanation:
> the i's are individual ids, the v's are data values.
> Without such explanation, it is unclear why there are two
> lines for oneOf.

Added qualifiers into the table.

> First sentence in Section 3:
> replace "the abstract syntax" by the OWL/DL abstract syntax
> (to use the recently introduced improvement to terminology)
> and mention that OWL Lite is not dealt with separately.
> (Instead of such a sentence only in Section 4, this could
> be stated here for both Sections 3 and 4.)

Added.  I think that it deserves to be restated in Section 4.

> Definition of abstract OWL interpretation:
> Jan Wielemaker and Guus mentioned to me that they needed to recall the
> 2^X notation.  In fact, it is preferable to use the notation P(X) 
> for power set: this is more mnemonic, more 
> widely used in mathematical theories, and does not need the 
> use of ^ to simulate superscripts.
> Suggestion: use notation P(X) (with P italics), and mention briefly 
> what power set means.


> Section 3.2: table
> This table is called "Description Interpretation table".
> However, the last five entries do not deal with descriptions
> but with "fact fragments".

Changed to EC Extension Table.

> The table in Section 3.2 uses single arrows for implication.
> The standard use of arrow is in function notation, also appearing
> in this section.  I suggest to move for implication to double
> arrows: =>, a more standard notation anyway.

Changed instead to ``implies''.

> Near the end of the section there is the sentence:
> "An Abstract OWL interpretation, I, satisfies an OWL ontology, O, 
> iff I satisfies each axiom and fact in the imports closure of O."
> Suggestion to add the following sentence to clarify a point that
> is left implicit in the entire section:
>    This implies that the vocabulary V of the interpretation includes 
>    all the URI references included in the imports closure of O.

I added this to the wording at the beginning.

> An abstract OWL ontology should in my view not have a capital
> first A in the word abstract (as is done often).

I'm leaving this is as is to try to give ``Abstract'' a technical flavour.

Received on Friday, 17 January 2003 11:34:55 UTC

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