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Re: Literals representing people?

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Mon, 29 Sep 2003 10:40:34 +0300
To: ext Bill de hÓra <dehora@eircom.net>, Benja Fallenstein <b.fallenstein@gmx.de>
Cc: Garret Wilson <garret@globalmentor.com>, Sandro Hawke <sandro@w3.org>, Graham Klyne <gk@ninebynine.org>, <www-rdf-interest@w3.org>
Message-ID: <BB9DBCA2.17AC%patrick.stickler@nokia.com>

On 2003-09-28 14:49, "ext Bill de hÓra" <dehora@eircom.net> wrote:

> 
> Benja Fallenstein wrote:
> 
> ...
>> But I may be wrong-- I think it would be good if some other members of
>> the list, in particular members of the core WG, could speak up on how
>> literals are to be interpreted in cases like this.
> 
> Any interpretation of a Literal is (must be) determined by the
> property it hangs off. Literals do not have a denotation (that's why
> they're literal) - although typed literals confuse the matter slightly.

I think it's fair to say that any property can can (though need not)
affect the interpretation of an object in various ways, regardless
of whether the object resource is denoted by URIref, literal, typed
literal, or blank node.

The property can have rdfs:range assertions which allow one to infer
rdf:type assertions about the object resource (which may or may not
conflict with explicit type assertions that may exist). The property
can have semantics relating to unit of measure which augment a typed
literal value, such that the total meaning of a statement may express
"ten miles" even if the object alone only denotes the integer value
'ten'. The property may even have extra-RDF semantics known to an
application, but not expressed in a way meaningful or accessible to
RDF or OWL processors, which results in different interpretations of
the same statement by RDF-only applications versus those applications
having that extra knowledge about what the property "means". E.g.
properties which take plain literal values in the RDF graph, which
are actually interpreted as lexical forms of an implicit datatype
not referred to in the RDF, such that RDF-only applications will
make entailments based on string values that differ from the proprietary
applications making entailments based on some typed value.

The golden rule, IMO, insofar as portable interchange of knowledge is
concerned, is to say as much as you can in RDF, so that little or no
special extra-RDF knowlege is brought to bear by any applications
on its interpretation.

If you don't *mean* the value to be a string, but to actually be
something else (other than just the name of that something else)
don't use a plain literal.
 
>> I would take the view that a plain literal always denotes a (character
>> string, language tag) pair and that properties that can take plain
>> literals need to be defined in a way that makes this a reasonable
>> interpretation. Typed literals can be used to refer to things like
>> integers.
> 
> Exactly.

Yup.

Cheers,

Patrick

--

Patrick Stickler
Nokia, Finland
patrick.stickler@nokia.com
Received on Monday, 29 September 2003 03:40:43 GMT

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