-----Original Message-----
From: denny.vrandecic@wikimedia.de
To: wikidata-l@lists.wikimedia.org
Subject: Re: [Wikidata-l] Expiration date for data

We will have a time datatype, and every property is strongly typed. This is also true for properties used as qualifiers.

Regarding the priority of qualifiers: very high. They are the next major UI feature to be deployed, and as far as I can tell from the progress of the team it looks like they will be deployed in April.

Cheers,
Denny
"every property is strongly typed" is clear, as you refer to datatypes, but not to "types" in the rdf:type sense, which of course are owl:Class things. When talking about owl:Class things it's nice to reference an OWL ontology, which maybe I've missed, from Wikidata. So I've learned from sniffing around that Wikidata's ontology is going in the direction of http://d-nb.info/standards/elementset/gnd. And that P107 is semantically identical to rdf:type.
 
Is this correct? If so, will you add "rdf:type" as an alternate label?
 
Although I disagree with some of below which I ran across at https://news.ycombinator.com/item?id=5328472, I do note that P107 on Wikidata is entitled "main type (GND)" among other indications. How does adopting a specific ontology accord with the view in your blog strenuously promoting folksonomies over ontologies?
 
That is, a folksonomy in the sense that owl:Class's are implicitly defined, whose "instances" are associated as a "class" by virtue of possessing in common certain properties and or property values. IOW, your blog implies little need to define "classes" at all. You face a challenge though because soon people want to attach a name to the bundle of properties and-or property values that comprise a "class" of things, to refer to them as a collection.
 
Any light you can shed about ontology plans for Wikidata would be appreciated!
thanks - john
 
emw 15 days ago | link

Property P107 (http://www.wikidata.org/wiki/Property:P107) has emerged as Wikidata's de facto upper ontology. It currently consists of six main types: person, organization, event, creative work, term, and geographical feature. It's essentially a clean port of the high-level entities from the GND Ontology -- a controlled vocabulary developed by the German National Library and released last summer (http://d-nb.info/standards/elementset/gnd).

There's a fair amount of debate over that property. Are those current high level types (person, place, work, event, organization, term) a good fit for a knowledgebase that aims to structure all knowledge and not just library holdings? Does classifying subjects like inertia, DNA, Alzheimer's disease, dog, etc. as simply "terms" make sense?

More reading related to Wikidata, ontology and types: https://blog.wikimedia.de/2013/02/22/restricting-the-world/.