Wikidata:WikiProject Ontology/Problems/High order metaclasses

Problems with higher order metaclassesEdit

A class can be identified as such by itself being a subclass of another class, by having another class be its subclass, or most directly by having instances. These provides three different mechanisms for detecting higher order classes as well, as the following queries illustrate.

These are only looking at direct instance-of relationships up the hierarchy. The most general query along these lines would look like, for example:

select DISTINCT ?item WHERE
  { ?metametaclass wdt:P31 ?item .
    ?metaclass wdt:P31/wdt:P279* ?metametaclass .
    ?class wdt:P31/wdt:P279* ?metaclass .
    ?otherclass wdt:P279 ?class . }

Try it!

However this times out in WDQS.

'concept'Edit

concept (Q151885) comes up as a high-level metaclass in many subclass of/instance of trees; for example:

but concept then has two more levels above it that cross the instance-of (metaclass) leap:

symbol (Q80071) itself also appears frequently near the top of the ontology trees. This should probably be cleaned up.