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Re: Usage of rdfs:label

From: Richard Cyganiak <richard@cyganiak.de>
Date: Thu, 15 Sep 2016 14:15:12 +0100
Cc: Antoine Zimmermann <antoine.zimmermann@emse.fr>, public-rdf-comments@w3.org
Message-Id: <A3C0A44D-ACAE-4A94-B6FC-02ADFCEC4179@cyganiak.de>
To: Felicja Sobczyk <felicja.sobczyk@kueea.info>
Felicja,

rdfs:label is for human-readable labels.

You say: “If the label literal were to be used as a replacement for the URI, then I would not know what resource is the label for.”

That’s right. But if you need to know *exactly* what resource the label is for, then why would you replace the URI with the label? If you need a precise, globally unique identifier, then use the URI. If you want something a bit shorter, use the canonical prefixed name such as rdfs:Resource. If you need something that looks like a normal end-user friendly string for rendering in an end-user interface, use the rdfs:label.

You say: “There is nothing in this label telling me that "Resource" is a class.”

That’s right. That’s why there is not just an rdfs:label but also an rdf:type!

Labels are just that—labels. They don’t tell you everything about a resource, and are not necessarily unique.

rdfs:Resource is a difficult example to make these distinctions clear, because it’s a metamodelling construct with a very specific meaning, and not a domain class. The distinction should be clearer if you consider a domain ontology like schema.org. It has classes for things like TV episodes, music playlists, bus trips, and so on. These terms may show up in end-user applications. The label presented to an end user should be “TV episode”, not “TVEpisode” or “schema:TVEpisode”. So, the rdfs:label should be “TV episode”, not “schema:TVEpisode”.

Also consider multilinguality. Labels can be translated into different languages. If we had labels like “rdfs:Resource” or “schema:TVEpisode”, a translation would not be meaningful.

Best,
Richard



> On 15 Sep 2016, at 12:26, Felicja Sobczyk <felicja.sobczyk@kueea.info> wrote:
> 
> Dear Antoine,
> 
> I understand that the definition of rdfs:label is outlined by the RDF
> Schema specification. I asked, because the ontology returned by
> requesting <http://www.w3.org/2000/01/rdf-schema> (and others) returns
> a document with the labels I mentioned. I found it wierd. I should have
> probably be more expressive about it.
> 
> I would rather expect the labels to at least contain an "rdfs:" prefix,
> so that the label is not, for example "Resource", but "rdfs:Resource".
> The label of "rdfs:Resource" would name the resource that is the class
> of RDF resources as defined by RDF Schema in the general, universal
> context. Such a label is also used in all specifications I have read.
> I just don’t understand why the labels differs from the specification.
> 
> If the label literal were to be used a replacement for the resource URI,
> then I would not know what resource is the label for. There is nothing
> in this label telling me that "Resource" is a class; "rdfs:Resource"
> would, because I am familiar with this (more expressive) label. It’s
> more natural.
> 
> Was those documents produced by people other than those that have
> written the specifications? Although, now that I am writing it,
> I noticed that these is also a back-referenece in the form of
> rdfs:isDefinedBy, so I’m maybe I’m being too picky here.
> 
> I wasn’t sure what would be the right design decision in a vocabulary
> I’m writing as a hobby. I asked to be certain whether I ought to define
> my properties as sub-properites or define them as distinct from
> rdfs:label. The labels I saw confused me about the meaning of this property.
> 
> If I should be prioritizing the text of the specification, then your
> answer is enough.
> 
> Sincerely,
> Felicja
> 
> On 29/08/16 11:08, Antoine Zimmermann wrote:
>> Dear Felicja,
>> 
>> 
>> The intended meaning of the property rdfs:label is explained in the
>> recommendation RDF Schema [1].  The property should be used to provide a
>> human readable name for a resource.  It very often happens that
>> rdfs:label (like all standard properties) is missused.  Considering the
>> intended meaning of rdfs:label, one should not use camelCase or
>> underscore_names as a label, IMHO.  Yet, what "human-readable" means is
>> subject to interpretation and one could argue that camelCase identifiers
>> are perfectly human-readable.
>> 
>> 
>> Best,
>> --AZ
>> 
>> [1] Dan Brickley, R.V. Guha (eds.). RDF Schema 1.1, W3C Recommendation
>> 25 February 2014. Section 3.6, rdfs:label.
>> https://www.w3.org/TR/rdf-schema/#ch_label
>> 
>> Le 27/08/2016 23:18, Felicja Sobczyk a écrit :
>>> Excuse me, what is the intended usage of rdfs:label?
>>> What the currently deployed software expects from the property value?
>>> 
>>> By examining RDF, RDF Schema and OWL2 vocabularies, I can see that all
>>> terms contain their local names as their labels. Why? Why was such
>>> a label chosen here? If it is supposed to be a human-readable name for
>>> the resource, then why are there no spaces and the name is written in
>>> camelCase? How is this property indended to be used by applications?
>>> 
>>> Is there some kind of context for the human readability that the
>>> specification mentions?
>>> 
>>> Sincerely,
>>> Felicja
>>> 
>> 
> 
Received on Thursday, 15 September 2016 13:15:43 UTC

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