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RE: OWL working drafts - feedback

From: Emery, Pat <pemery@grci.com>
Date: Mon, 9 Sep 2002 10:42:58 -0400
Message-ID: <4E4858A8C481D5119DA100B0D0796B8219B145@thumper.va.grci.com>
To: "'Peter F. Patel-Schneider'" <pfps@research.bell-labs.com>
Cc: public-webont-comments@w3.org, patemery@att.com

I can see and agree with the rationale of allowing me to specify properties
with no values.  My uneasiness should have been better expressed as, "Why
the positive-integer restriction of minCardinality?".

Maybe what is missing is more description of the rational on the cardinality
definitions in the document both under OWL and OWL-LITE.

5.1.2 does not seem to allow for minCardinality 0 | maxCardinality 0 |
minCardinality 1 maxCadinality 0.  If this is correct I think it should be
spelled out in the text of the abstract Syntax document as well as some of
the other documents that seem to specify only that the cardinality
descriptors are restricted to 0 or 1.

5.3.3/5.2.3 allows cardinality 0 under cardinality as a non-negative-integer
but not minCardinality 0 under minCardinality as a positive-integer. If
cardinality 0 is expanded out to minCardinality 0 maxCardinality 0.  This
seems to imply minCardinality can have a value of 0 but only if
maxCardinality is also 0.  Again this is ok but should definetly be spelled
out if this is correct.

Also of slight note is that the http://www.w3.org/2002/07/owl document has
all the cardinalities listed as non-negative integers.


-----Original Message-----
From: Peter F. Patel-Schneider [mailto:pfps@research.bell-labs.com]
Sent: Saturday, September 07, 2002 9:56 AM
To: pemery@grci.com
Cc: public-webont-comments@w3.org; patemery@att.com
Subject: Re: OWL working drafts - feedback


> Section 5.3.3 Shouldn't the third cardinality line have max-cardinality be
> positive-integer.  Otherwise this seems to allow min>max where max=0.
> Shouldn't there be a statement additionally that states that min < max.

It is possible to state minCardinality=5 maxCardinality=4.  There will be
no instances of the restriction but this is not an error.  It doesn't help
to rule this out syntactically.

Maximum cardinality of 0 even more acceptable, as all it is stating is that
instances of the restriction have no values for the property.  This is
needed for definitions like bachelor, a man with no wife.


> Pat Emery
Received on Monday, 9 September 2002 10:43:13 UTC

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