Dear all,

I am speaking from OWL-point of view and agree with most of the other writers. 
Concerning the P1-issue:
- rdfs:label has rdfs:Literal as range
- P1 in OWL typically is an object property and not a datatype property. It has E41 as a range and E41 is not in the E59 primitive value subtree. Its subclasses are via multiple inheritance, but it does not hold for E41 itself.
- If you declare rdfs:label a subproperty of P1 you are changing in fact the definition of rdfs:label and the definition of E41. This means you simply change the data on nearly the whole world without even having a glance at a single dataset. This is not only a worst-practice but would lead to massive inconsistencies when it comes to reasoning with OWL. I don't want to tell you what you should do in rdf - because rdf is more flexible here. But it does not seem logical to me. Ontology alignment is a difficult task.
I  understand that it might be helpful in some scenarios. But I think it would confusing if the official CIDOC CRM RDF file would do ontology integration that way. Furthermore RDF is just one implementation of CIDOC CRM and typically when it comes to implementation only primitive datatypes are replaced by the implementation - not object properties.

In the Erlangen CRM we use:
- owl:Class for the classes,
- we have some owl:Restrictions (74)
- owl:ObjectProperty for the object properties
- owl:DatatypeProperty for the datatypes
- owl:inverseOf for the inverses
If I didn't miss anything, thats all. See http://erlangen-crm.org/200717/

So the difference between OWL and RDF variant won't be big after adding owl:inverse and if you start using owl in your ontology definition it is pretty straight forward to use OWL completely anyway ;-)

We had a long discussion on shortcuts - I think the conclusion was we hardly have shortcuts in CIDOC CRM that could be used as Property chains as the implications are not strong enough. Martin probably can add some in here. 

Best,

Mark





Am Do., 9. Sept. 2021 um 18:55 Uhr schrieb Martin Doerr via Crm-sig <crm-sig@ics.forth.gr>:
Dear Francesco,

This is a complex issue, which has been discussed in length in 2018 and basically was spelled out in the implementation guidelines for RDFS by Richrad Light and me.

All these questions you pose have been taken into account carefully. The text may need improvements, but I'd kindly ask all CRM-SIG members having respective questions to read it carefully and give us feedback.

Let me explain just a bit here from the side of logic, which is tricky and not the usual reasoning we apply within the CRM:

A superproperty is not equivalent to a subproperty. A superproperty is only implied by a subproperty.
 
 Therefore: Once E41 Appellation has no necessary property, an instance of E41 Appellation without having a property of its own does not violate the range of the superproperty. Its just a poor case.

(But it is completely true that rdfs:label is without properties. From the time of RDFS 1.1 on, which recommends the use of xsd values in literals, there are hidden properties in the label, such as the language tags.)

This statement does also strictly not hold: "This class is subclass of Symbolic Object and Legal Object, therefore a E77 Persistent Item and not a E62 String which is a E59 Primitive Value",

because a) there is no axiom in CRM saying that Persistent Item and E62 String are disjoint.
                b) There is no declaration in the RDFS implementation that rdf:Literal equals E62 Sting or
                        E59 Primitive Value.

Obviously, RDFS makes rich use of Literal, packing stuff like WKT geometric values  into them, which are used in geo-enabled triple stores.

With the superproperty declaration, we say that whowever uses rdfs:label refers to a name (E41 Appellation). Unfortunately, RDFS does not allow us smarter things to do, but this gives the right answers to queries.

All the best,

Martin

On 9/9/2021 6:46 PM, Francesco Beretta via Crm-sig wrote:

There was unfortunately a copy-paste issue in my email.

Le 09.09.21 à 17:35, Francesco Beretta a écrit :
The P1 is identified by (identifies) property has E41 Appellation as range. This class is subclass of Symbolic Object and Legal Object, therefore a E77 Persistent Item and not a E62 String which is a E59 Primitive Value.

Therefore an instance of E41 Appellation — rdfs:label —> '[label]', right ? So it crm:P1 cannot be equivalent to rdfs:label?


I mean:

An instance of E41 can have this property:
E41 Appellation — rdfs:label —> '[label]', right ?

So the crm:P1 property cannot be equivalent to rdfs:label, right?


With my apologies

Francesco



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 Dr. Martin Doerr
              
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