W3C home > Mailing lists > Public > www-rdf-logic@w3.org > June 2001

RE: DAML-S expressiveness challenge #1

From: Marcelo Tallis <mtallis@teknowledge.com>
Date: Wed, 20 Jun 2001 16:44:40 -0700
To: "Ian Horrocks" <horrocks@cs.man.ac.uk>, "David Martin" <martin@ai.sri.com>, "Dan Connolly" <connolly@w3.org>
Cc: <www-rdf-logic@w3.org>
Message-ID: <AMEJJKLNDKJFJMKHDPOJGEDHCDAA.mtallis@teknowledge.com>

> You can do this now, or something close. Simply introduce a new
> property called say "P1_or_P2" such that both P1 and P2 are asserted
> to be subProperties of P1_or_P2. Now you can use a cardinality
> restriction to assert that a class C has at most one P1_or_P2. Thus if
> some instance of the class is related to individual x by P1 and
> individual y by P2, then x=y.

I believe this wouldn't work. What was requested (I think) was that two
*different* instances representing the first two steps of a process (e.g.,
s1 and s2) have a property each (e.g., input and output) with the same value
(e.g., the credit card number). Cardinality restrictions apply to single
instances in isolation even when they belong to the same class. For example,
a person can have at most one father, but that doesn't mean that two
different persons will have the same father. In your suggestion, the
cardinality restriction applies to each individual instance in isolation
(e.g., s1 and s2 cannot have more than one credit card number each) but does
not implies that s1 and s2 will have the same credit card number.
Received on Wednesday, 20 June 2001 19:35:53 UTC

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