I am in the process of creating a better way to map CSL types to Wikidata types together with Jakob Voß, and while listing all subtypes of web page
, I came across a number of these cases (link):
#defaultView:Graph
SELECT ?a ?aLabel ?b ?bLabel WHERE {
wd:Q58803899 wdt:P279* ?a .
?a wdt:P279 ?b .
FILTER EXISTS {
?b wdt:P279* wd:Q386724 .
}
SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}
I’m no expert on Wikidata data models, nor on the semantics of each of those items in specific, but I’m pretty sure Count of Barcelos (Q58803899) is not a subclass of web page (Q36774). However, the individual parts seem pretty reasonable, so where does it go wrong then?
Luckily, the description of subclass of (P279) provides some good guidance:
all instances of these items are instances of those items; this item is a class (subset) of that item.
So let’s check those:
- All counts of Barcelos are Portuguese counts (
conde
), as Barcelos lies in Portugal - All condes are counts
- Counts are not hereditary titles themselves, so I think this should be a instance of (P31). Also, counts are indirectly subclass of
royal or noble rank
throughhereditary title
s, but directly instance ofroyal or noble rank
. - Hereditary titles do not seem like an exact subclass of royal or noble ranks to me, but it passes the basic test
- I am unsure about royal or noble rank as subclass of rank, since the latter seems way more abstract, but perhaps that’s the point
- (rank -> first-order metaclass) I have no idea what the intention with these metaclasses is, so I’m going to assume this is all correct (bold move)
- first-order metaclass -> fixed-order metaclass
- fixed-order metaclass -> Wikidata metaclass: “class of classes, class whose instances are classes”
- Wikidata metaclass -> class or metaclass of Wikidata ontology (should maybe be P31 as well, still no clue though)
- class or metaclass of Wikidata ontology -> Wikidata item: finally back into some form of concrete-ness. Problem being, not all instances of
royal or noble rank
s areWikidata item
s, so something went wrong somewhere in between, maybe even at (6). - Wikidata item -> Wikidata internal entity
- Wikidata internal entity -> Wikidata internal item
- Wikidata internal item -> MediaWiki page
- MediaWiki page -> web page: actually pretty reasonable, instances of
Wikidata item
s areweb page
s.
There are a little less than 900 instances of web page
so the impact is smaller than I had expected, but it’s still annoying. There are 191 subclasses of conde
, not to mention the total of 280 royal or noble ranks that have no business being a subclass of web page
.