RE: related measurements (MATCHING) for property names

... and as well as the relations defined formally in OWL and slightly less formally in SKOS, there are other equivalence-like relations in FOAF, DC, and VoID which may belong in general taxonomy of these things.

Simon Cox

From: Christophe Dupriez [mailto:dupriez@destin.be]
Sent: Friday, 6 July 2012 3:34 PM
To: Simon Spero
Cc: Kalpa Gunaratna; public-esw-thes@w3.org
Subject: Re: related measurements (MATCHING) for property names

Thank you Kalp to share your interesting question!

Dear Simon and Mike,

Your answers show that there is a need for a document clarifying the possible equivalence relations between "subjects".
With a precise "semantic" for each (semantic meaning for me "what automated processing a machine can make based on that relation?").

* For instance, "skos:narrower" is meaning "Concepts linked can be used to automatically extend a search equation"
* I am often wondering about "skos:related": does it means "Concepts linked should be presented to the user as alternate search" (i.e. what is the desired automated behavior?)
* And "skos:narrowMatch": "Concepts linked can be used to automatically extend a search equation if they are reachable within a reasonable computing effort"
* owl:sameAs has a very powerful semantic (consider the other subject as a perfect alias for every computing purposes)...

Do you have a small set of references for such a recapitulation?

Have a nice day!

Christophe
@ChristopheDupri

Le 5/07/2012 23:33, Simon Spero a écrit :
On Thu, Jul 5, 2012 at 2:43 PM, Kalpa Gunaratna <kalpa@knoesis.org<mailto:kalpa@knoesis.org>> wrote:
Hi,
   I know that SKOS has several matching properties for concepts in ontologies like skos:closeMatch, skos:broadMatch, skos:narrowMatch and skos:relatedMatch . I want to get some notion to say that two property names in two ontologies relate or closely match each other. Since SKOS is defined for concepts, I think I can't use it for my purpose here. For example, I want to use something like 'SKOS:closeMatch" for two property names if they mean the same in two datasets. I want to know whether there is work going on regarding this issue and if so point me to a resource so that I can use it for my purpose here. Thank you.

There are several possible answers depending on what is intended by (a)"two property names"/ (b)"mean[ing] the same"/ (c) "in two datasets".

The reading that seems most plausible to me is that:

1: There are two sets of individuals DS1 and DS2.   To simplify things, we can let D1 and D2 be classes whose extensions are the subjects of assertions in  DS1 and DS2   (c)
2: There are two predicates, P1 and P2       (a)

3: If two properties named by A and B,  mean the same thing in any and all contexts, then the properties have  identical extensions  (forall (?x ?y ) (iff (A ?x ?y) (B ?x ?y)).
    If this is the case, then they are owl:equivalentProperty  .  This does not mean that they are the same property; it just means that they have the same extension.  If the two properties are really the same property, then the properties are also  owl:sameAs  .

4: If two properties named A and B  are not owl:equivalentProperty , there must be some combination of subject and object where  A holds, but B does not.
If the properties do have the same extensions for classes D1 and D2,  we can express this in CLIF as:
       (iff  (D1or2 ?x) (or (D1 ?x) (D2 ?x))
       (forall ((?x D1or2)  ?y) (iff  (A ?x ?y) (B ?x ?y)))

In OWL we are a bit more restricted: however,  we can get the same net result we create a new property C which is an rdfs:subProperty of  both A and of  B, and whose rdfs:domain is D1 or  D2, and replace all assertions of A and B in DS1 and DS2 with assertions of C.   From any assertion ?x C ?y, we can infer ?x A ?y and ?x B ?y.  We can also infer that ?x type D1 and ?x type D2 cannot both be false.

Simon