# R: questions on assertion

From: Franco Salvetti <franco.salvetti@tiscalinet.it>
Date: Wed, 10 Jul 2002 13:58:55 +0200
Message-ID: <000e01c22809\$2e8e7560\$6b050a3e@hobbit>

Cc: "Alessandro Provetti" <provetti@gongolo.usr.dsi.unimi.it>
```
Hi,

1) There are two assertion about the domain of a property, there is a
subproperty of it with an own domain, and an assertion about *something*
using the subproperty:

<rdfs:domain rdf:resource="http://example.org/ont#A"/>
<rdfs:domain rdf:resource="http://example.org/ont#B"/>
</rdf:Description>

<rdfs:subPropertyOf rdf:resource="http://example.org/ont#p"/>
<rdfs:domain rdf:resource="http://example.org/ont#C"/>
</rdf:Description>

<ont:q rdf:resource="http://example.org/ont#blabla"/>
</rdf:Description>

/* other useful thinks are supposed already stated */

There are many thinks that we have to consider:

1) What is the domain of ont:p?
2) What is the domain of ont:q?
3) How can I verify that ont:something is in the domain of ont:q?

Please do consider every possible situation:

ont:A and ont:B are *disjoint*
ont:A and ont:B have an not empty *intersection*
ont:C could be a rdfs:subClassof ont:A
ont:C could be a rdfs:subClassof ont:B
ont:C could be a rdfs:subClassof (ont:A U ont:B)
ont:C could have some elements outside (ont:A U ont:B)
[more situation]

I think that is important, in order to reject an assertion, to solve this
problem.

In my personal opinion it is not sufficient know that:

<rdf:type rdf:resource="http://example.org/ont#C">
</rdf:Description>

to imply that ont:something is in the valid domain of ont:q because ont:C
could be outside the domain of ont:p and I hope that is impossible that a
subproperty had a domain *larger* than its super-property. I am refering to
the definition of subrelation as a subset of a relation.

In my paper experiments I see problems considering that the domain of ont:p
is the union of ont:A and ont:B
or considering their intersection as a domain of ont:p. This because we do
not have a simply way to say *where* is ont:C just using rdf:subClassOf.

The question is general and related to the inheritnace of the domain for a
subproperty in the case in which there are no other assertion about its
domain and the case in which there are other assertion about it.

sincerely
Franco
```
Received on Wednesday, 10 July 2002 07:50:57 GMT

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