- From: Dan Brickley <danbri@w3.org>
- Date: Sun, 09 Oct 2005 22:18:51 +0100
- To: Charles McCathieNevile <chaals@opera.com>
- Cc: public-esw-thes@w3.org
Charles McCathieNevile wrote: > > On Sat, 08 Oct 2005 10:57:17 +0200, Bernard Vatant > <bernard.vatant@mondeca.com> wrote: > >> Your "descargabile de la red" is more explicit than the english >> original, which seems to >> have been problematic also for the german translator. The same in >> french would be indeed >> "téléchargeable sur le Web" rather than "addressable". >> >> But since the range of skos:symbol is dcmitype:image should not we >> stick to the definition given by DCMI? > > > I think not, for two reasons: > > Alistair admitted to being "lazy" in writing the property, but the > fact that we have a lot of clues about what he meant to say, in my > mind, justifies us doing a good translation of what he meant, in > order to provide more guidance for people relying on the non-english > version. > > The second is that the presence of real text, not just a note about > the range, is that there might be something more than the minimum > that can be inferred from the range. For example we might read the > note and thus not be surprised when the property is "upgraded" to use > a range of something more tightly defined than dct:image Yep, quite right. At the meta-level, there's a piece of work to be done here (perhaps by a future incarnation of SWBP WG) describing classes of change to RDF vocabularies. It's related to the VM work (which I wish I'd had more time to spend on...). case 1: making a range more restrictive eg 2005 you say "the rdfs:range of eg:myproperty is xyz:SomeClass" and then in in 2006, you change the schema to assert that the rdfs:range is pqr:SomeOtherClass", ... and the latter is a subclass of the former. So before you were saying "whenever you see a true usage of eg:myproperty, you can be sure it is pointing at an instance of an xyz:SomeClass". Now you're saying "whenever you see it, you can be sure you're pointing at an instance of a pqr:SomeOtherClass". As you point out (and the RDFS spec tries to say too[1], folk shouldn't simplistically assume that the rdfs:range of a property means that any instance of the range class is an applicable value. They need to know more about the meaning of the property. What the RDFS semantics guarantee is just that, if you see the property with some given resource as its value, you know the type of that resource. Not that all other things of that type could have been used. We need some notion of "fairness" here. Depending on what exactly the text definition, examples, mainstream practice etc etc amount to, the community will react in various ways. Eg. "hey, unfair, your examples in various specs led me to believe the property was applicable to these things which did fall within the formal range of the property" versus "ok, that's reasonable; the new range more accurately captures the commonly understood meaning of the term". In the Dublin Core scene, some of us are wondering how a restriction of the range of dc:creator etc would be perceived. My guess is that it won't be perceived well... but that's another thread. case 2: making a range less restrictive This is a bit different. It basically removes the justification for data that was inferred on the basis of range/domains. That new data might still happen to be true, but claims in the schema are no longer available as 'evidence'. There are a lot more variations than I've listed here, too... cheers, Dan [1] http://www.w3.org/TR/rdf-schema/#ch_introduction
Received on Sunday, 9 October 2005 21:18:46 UTC