Sounds not uninteresting, but without the context of the discussion it’s
hard to understand what the problem actually is. Could include more details
I googled a bit and found that a « transitive over » usecase could be
* researcher Livingstone « explores » Egypt
* Egypt is a part of Africa
then we can conclude that researcher livingstone explores Africa
This would mean that the « explore » property would be transitive over «
part of ».
An example of this could be of course « instance of » who is of course
transitive over « subclass of ».
Yet « subclass of » is of course a transitive property by itself. If all
mammals are animals (so ''mammal subclass of animal')' and all animals
organism ''animal subclass of living organism'', then of course all
are living organisms.
As for transitivity of « part of » of course if A is a part of B and C is a
part of A, then C is a part of B. The thing is that someone that studies,
say a lineage of cell of some kind of animal could not necessarily
considering to study the animal itself, so « studies » could not be
considered to be transitive over « part of ».
What exact reasoning problem do you have in mind ?
Le sam. 21 mai 2022 à 17:56, Thad Guidry <thadguidry(a)gmail.com> a écrit :
I wanted to share my reply to a recent Telegraph
Thad Guidry, [5/21/2022 10:22 AM]
[In reply to Nikki]
Agree somewhat, however in the case of P31 we already have P6609 that
describes the general SKOS/OWL "transitive over" and we added the
value-type constraint https://www.wikidata.org/wiki/Q21510865
transitive property https://www.wikidata.org/wiki/Q18647515
But that was not the case with P279 ... where instead we stated that P279
itself is an instance of transitive property ... which is what probably
[[wikilinksbot]], [5/21/2022 10:22 AM]
) – instance of
) – value hierarchy property
) – subclass of
Thad Guidry, [5/21/2022 10:26 AM]
So P279 is a https://www.wikidata.org/wiki/Q18647515
and P31 is not.
[[wikilinksbot]], [5/21/2022 10:26 AM]
) – subclass of
) – instance of
Thad Guidry, [5/21/2022 10:29 AM]
Details here: https://www.w3.org/TR/owl-ref/#TransitiveProperty-def
Thad Guidry, [5/21/2022 10:38 AM]
So... (lolol) .... through transitivity once an item becomes an instance
of a class... then it automatically inherits all properties of that
class... but only and strong ONLY WHEN it is considered an instance of a
class... and not before.
Reasoners, interpreters (external, custom code, institutions, etc.) might
apply transitivity "slightly" differently for different contexts, and might
bucket some items prematurely to be considered an instance of a class ...
but generally, the old adage is that of the above paragraph... only once it
is considered an instance of.
The problem as often seen in Wikidata is that sometimes higher classes are
currently not abstract enough sometimes to fulfill broader roles... *and
hence... a broader higher class oftentimes just needs to be created to make
things in the hierarchy a bit more sensical.*
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