You're not really supposed to use a named blank node as if it had a specific meaning.
rdf:nil represents the empty list and is a good stand-in for "no value" situations. On Fri, Feb 26, 2016 at 7:32 AM, James Heald <[email protected]> wrote: > 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{%0A%20%20%3Chttp%3A%2F%2Fwww.wikidata.org%2Fentity%2FQ595133%3E%20p%3AP279%2Fps%3AP279%20%3FsuperClass%0A} >> <https://query.wikidata.org/#SELECT%20%3FsuperClass%20WHERE%20%7B%0A%20%20%3Chttp%3A%2F%2Fwww.wikidata.org%2Fentity%2FQ595133%3E%20p%3AP279%2Fps%3AP279%20%3FsuperClass%0A%7D> >> >> >> 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 >> >> > > _______________________________________________ > Wikidata mailing list > [email protected] > https://lists.wikimedia.org/mailman/listinfo/wikidata > -- Paul Houle *Applying Schemas for Natural Language Processing, Distributed Systems, Classification and Text Mining and Data Lakes* (607) 539 6254 paul.houle on Skype [email protected] :BaseKB -- Query Freebase Data With SPARQL http://basekb.com/gold/ Legal Entity Identifier Lookup https://legalentityidentifier.info/lei/lookup/ <http://legalentityidentifier.info/lei/lookup/> Join our Data Lakes group on LinkedIn https://www.linkedin.com/grp/home?gid=8267275
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