W3C home > Mailing lists > Public > public-vocabs@w3.org > May 2014

RE: ItemList

From: Markus Lanthaler <markus.lanthaler@gmx.net>
Date: Wed, 14 May 2014 21:32:39 +0200
To: "'W3C Web Schemas Task Force'" <public-vocabs@w3.org>
Message-ID: <00bc01cf6fab$4535fad0$cfa1f070$@gmx.net>
On Wednesday, May 14, 2014 7:54 PM, Dan Scott wrote:
> On Wed, May 14, 2014 at 07:14:14PM +0200, Markus Lanthaler wrote:
> >On Tuesday, May 13, 2014 9:26 PM, Jason Douglas wrote:
> >> Those are only there because it inherits from CreativeWork.  If people
want to
> >> use ItemList for all ordered lists, than we need to move that
inheritance down
> >> the chain, which is what Justin is proposing.  So only
EditorialItemList would
> >> inherit CreativeWork (and ItemList), while ItemList would not.
> >
> >No, that's not true (even though the way schema.org is rendered
> >suggests that it is the case). You can use any property, not just the
> >ones whose domain is that specific class (or a super-class thereof).
> Hmm. That assertion appears to be at odds with
> http://schema.org/docs/datamodel.html which states:
> """
> 2. We have a set of properties
>   1. each property may have one or more types as its domains. The property
>      may be used for instances of any of these types.
>   2. each property may have one or more types as its ranges. The value(s)
>      the property should be instances of at least one of these types.
> """
> In addition, under "Conformance" on the same page is the opening
> statement: "While we would like all the markup we get to follow the
> schema, in practice, we expect a lot of data that does not."

That doesn't mean that usage of these properties is disallowed for entities
of other types or that is invalid to have an entity with multiple types.

AFAIK, schema.org is still build on the open world assumption which means
that you can't infer that everything that isn't known to be true is
automatically false.

Markus Lanthaler
Received on Wednesday, 14 May 2014 19:33:11 UTC

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