[Pellet-users] does ‘allValuesFrom' restriction makes sense in an Open (and therefore potentially cruel ;-) World ?

[Raphael Coulonvaux]

   Hi,

I would like Pellet (1.5.1) to infer that some individuals belong to a class
whose definition contains both a 'someValuesFrom' and a 'allValuesFrom'
restriction (closure axiom pattern) but unfortunately it does not.

Remark : the individuals type inference gives the expected result if I
remove the 'allValuesFrom' restriction from the class definition.

So my question is : with the Open World Assumption, is it possible or not to
infer that an individual belongs to a class whose definition says that it
contains individuals that may be related by a specified object property to
ONLY individuals belonging to another given class ?

I attached a tiny test ontology 'only_test.owl' showing the problem.

Here is the Pellet inference result when the "Class2" definition does NOT
contain the 'allValuesFrom' restriction (look at the last inference result
line) :

owl:Thing
    test_only:Class1 - (test_only:individual1_Class1)
       test_only:Class11 - (test_only:individual2_Class11)
    test_only:Class2 - (test_only:individual3_Class2)
       test_only:Class21 - (test_only:individual4_Class2)

Here is the Pellet inference result when the "Class2" definition DOES
contain the 'allValuesFrom' restriction :

owl:Thing
    test_only:Class1 - (test_only:individual1_Class1)
       test_only:Class11 - (test_only:individual2_Class11)
    test_only:Class2 - (test_only:individual3_Class2,
test_only:individual4_Class2)
       test_only:Class21

As you may see on the second inference result last line,
"individual4_Class2" (that is asserted to belong to "Class2") is not anymore
inferred as belonging to "Class21" while it was in the first inference
result.
The "individual4_Class2" is related by the "requires" object property to
"individual2_Class11" (asserted to belong to "Class11").
The "individual4_Class2" is NOT related to any other individual and
therefore we could consider that it is ONLY related by the "requires" object
property to individual(s) belonging to "Class11", but Pellet does not infer
so.
Any idea ?

Raphaël Coulonvaux
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