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Feature Synopsis document: a review

From: <herman.ter.horst@philips.com>
Date: Mon, 16 Dec 2002 15:14:50 +0100
To: dlm@ksl.Stanford.EDU, Frank.van.Harmelen@cs.vu.nl, www-webont-wg@w3.org
Message-ID: <OFA9DCAAB1.07AED361-ONC1256C91.00475AA5-C1256C91.004E73B5@diamond.philips.com>
The Feature Synopsis document is becoming a very useful overview.

Below I include some comments about the version of November 20.
These are mainly editorial suggestions, and a few corrections.

- Apart from the historical reference to DAML+OIL in the last sentence 
of the first paragraph of section 1, all other (more than 10) 
references to DAML+OIL could be removed from the document.
It is natural that DAML+OIL is in the head of the authors of the document,
but for somebody who steps freshly into this document, without any 
knowledge
about history and DAML+OIL, these references annoyingly detract from the 
story. 
An alternative could be to combine all these comparison statements
to DAML+OIL near the end, in one special paragraph.  However,
I am in favor of simply deleting them from the document.

- section 2.2.4: replace "filler information" by value information,
as this is clearer.  Outside the DL world, the world filler is not
known with this meaning.  Moreover, the expression 'value information'
gives complete explanation: compare the text already contained after the
bullet that immediately follows 2.2.4

- section 3.1: first bullet: Class
"Classes can be made to be equivalent to or subclasses of intersections
of other classes or restrictions."
Here the word restrictions has not yet been explained in the text before.
I would delete the last "or restrictions" here.

- section 3.3: SymmetricProperty
"Note that properties must have appropriate domains and ranges in order 
to be made symmetric. "
This sentence erroneously implies that a property without domains and 
ranges
cannot be made symmetric.
Therefore, I suggest to replace it by something like:
Note that properties cannot be given arbitrary domains and ranges when 
made
symmetric."

- section 3.3: FunctionalProperty
"If a property is a FunctionalProperty, then it has no more than one value 

and it may have no values. "
This is not correct as stated.  It can be made correct as follows:
If a property is a FunctionalProperty, then it has no more than one value 
for each individual and it may have no values for an individual. 

"For example, hasPrimaryEmployer may be stated to be a FunctionalProperty. 
If an individual instance of Person has a primary employer, then that 
individual may not have more than one primary employer. "
The conclusion in the second sentence here already holds without its 
assumption.
Therefore, this second sentence can be simplified to:
Then, no individual may have more than one primary employer.

"This name is still under discussion"
Drop this sentence: the corresponding issue is closed.

- section 3.3: InverseFunctionalProperty 
remove the bracketed (unambiguous): this is the only place
where a bracketed addition appears in this way.
And, two lines below, the word unambigous already appears in a sentence.

"Thus the inverse of the property has at most one value <add: for each
individual>."
"The inverse of this property (which ...) has at most one value <add: for 
each individual>." (or more simply: is functional)

- section 3.3
"OWL Lite allows restrictions to be placed on the type of values for a 
property."
Restrictions are the most subtle part of OWL to explain.
I believe more explanation should be given here than just this sentence. 
As stated with this sentence, it seems
that restrictions restrict the extent of properties (see also the title
of 3.3), whereas in fact restrictions restrict the extent of classes.
The sentence on local retrictions, i.e. part of the second sentence of 
section 3.4, can already be given here, as allValuesFrom and 
someValuesFrom 
are also examples of such local restrictions.

- section 4: hasValue
remove the bracketed addition "also sometimes referred to as property 
fillers"
WebOnt has not chosen to use this DL-terminology.
The phrase property values is already entirely clear.
Received on Monday, 16 December 2002 09:17:02 GMT

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