These are used as placeholders for the meta-values "unknown value" and "no value" aren't they ?
On 26/02/2016 12:27, Markus Kroetzsch wrote:
Hi Stas, hi all,
I just noted that BlazeGraph seems to contain a few erroneous triples. The following query, for example, returns a blank node "t7978245":
SELECT ?superClass WHERE { http://www.wikidata.org/entity/Q595133 p:P279/ps:P279 ?superClass }
https://query.wikidata.org/#SELECT%20%3FsuperClass%20WHERE%20%7B%0A%20%20%3C...
I stumbled upon six cases like this (for P279): Q595133 (shown above), Q1691488, Q11259005, Q297106, Q1293664, and Q539558. This would be less than 0.001% of the 623,963 P279 statements, but it's still enough to have application code trip over the unexpected return format ;-).
Best
Markus