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Re: Cardinality of schema.org properties (ISSUE-5)

From: Gregg Kellogg <gregg@kellogg-assoc.com>
Date: Fri, 21 Oct 2011 13:30:17 -0400
To: Dan Brickley <danbri@danbri.org>
CC: Philip Jägenstedt <philipj@opera.com>, "jpanzer@google.com" <jpanzer@google.com>, "public-vocabs@w3.org" <public-vocabs@w3.org>
Message-ID: <16BF01E7-3E88-4CB4-B64E-7947EDA38C36@greggkellogg.net>
On Oct 21, 2011, at 4:56 AM, Dan Brickley wrote:

On 20 October 2011 10:19, Philip Jägenstedt <philipj@opera.com<mailto:philipj@opera.com>> wrote:
On Thu, 20 Oct 2011 01:22:02 +0200, John Panzer <jpanzer@google.com<mailto:jpanzer@google.com>> wrote:

I'm trying to determine how to know what the intended cardinality of any
given schema.org<http://schema.org> defined property.

I asked about this and got this answer: [1]

On Thu, Jun 16, 2011 at 06:56, Guha <guha@google.com<mailto:guha@google.com>> wrote:

Right now, it is always allowed to have multiple values.
In the future, we could/should introduce a property of properties that
specifies when a property may have only a single value.

Not exactly a satisfactory situation, but there it is.

Given that schema.org<http://schema.org> references an OWL vocabulary description [2], it would seem logical to use something like the following:

schema:CreativeWork a owl:Class;
  rdfs:label "CreativeWork"@en;
  rdfs:comment "The most generic kind of creative work, including books, movies, photographs, software programs, etc."@en;
  rdfs:subClassOf
    schema:Thing,
    [ a owl:Restriction; owl:maxCardinality 1; owl:onProperty schema:awards ].

[1] http://groups.google.com/group/schemaorg-discussion/browse_thread/thread/95dfc4aa1ab89dbf?pli=1
[2] http://schema.org/docs/schemaorg.owl<http://www.google.com/url?sa=D&q=http://schema.org/docs/schemaorg.owl&usg=AFQjCNG1drRv5wowQfnPxxRFeWwIp3Y3MA>

I've recorded this in an issue at
http://www.w3.org/2011/webschema/track/issues/5

Dan

Gregg
Received on Friday, 21 October 2011 17:31:52 GMT

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