RE: [OEP] Draft of a note on n-ary relations

Natasha

> > - The property "amount" seems to me a Datatype property ...
> > I would suggest to either get rid of it altogether ...

> I favor getting rid of it. This would mean using something other than
> purchase though (seems unnatural to define a purchasing event without
> an amount -- yo are right it doesn't add anything and only creates the
> confusion, but still). Perhaps borrowing or something like that.

The original sentence defining the situation has to be corrected in any case ...

"John buys a "Lenny the Lion" book from Mary for $15 as a birthday gift."

Should read certainly

"John buys a "Lenny the Lion" book for $15 *for* Mary as a birthday gift."

But in fact this sentence describes all mixed together two distinct events, the "purchase"
and the "gift".
Mary should not know anything about the former, and certainly not the amount - that would
be considered as rude from John, at least in France, maybe not in America, where $ is the
measure of everything :))

So, to get rid of the amount, let's focus on the gift rather than the purchase:

"John offers a "Lenny the Lion" book to Mary as a birthday gift".

With the following formal description

:Gift_1
a     :Gift ;
	:has_agent :John ;
      :has_recipient :Mary ;
	:has_object :Lenny_The_Lion ;
	:has_occasion :Mary's Birthday .

And change the Restriction on has_occasion to e.g. allValuesFrom :Event

Another picky remark : the identification of the gift object is somehow fuzzy here.
Is it an individual copy, or the generic publication defined e.g. by its ISBN number as
discussed before?
Accurately, it's a random instance of the publication, before the purchase, and it becomes
a singular, identified one as soon as it is signed up by John ("To Mary, for her 7th
birthday - John") and offered.
Should the example capture that, or sweep the difficulty under the carpet ?

> > - Why is there not any inverseOf for "purpose"?
>
> No reason, except that it didn't seem to be natural to have one.
> Perhaps it should be there.

Will be more natural with "has_occasion" and "is_occasion_for"

> > I can provide TM translation for the Lionish example, along the lines
> > of this paper, and a bit of XTM syntax if it considered relevant to include it in the
> > document.
>
> this would indeed be useful (Alan?). Could you make a pass at it? It
> would help though if you use an example very similar to the one in the
> note -- perhaps the same one (says she, right after saying she is going
> to change it :)

I will propose it for the above "gift" example if you agree it's better.
The best would be first to define the OWL-RDF syntax for it, to have
the URIs of classes and properties that will be used as "subjectIndicatorRef" in the XTM
syntax.
(I can provide both syntaxes).

Cheers

Bernard

Bernard Vatant
Senior Consultant
Knowledge Engineering
Mondeca - www.mondeca.com
bernard.vatant@mondeca.com

Received on Thursday, 6 May 2004 05:11:18 UTC