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[dxwg] foaf:page, not foaf:homepage (#1231)

From: Matthew Rawlings via GitHub <sysbot+gh@w3.org>
Date: Tue, 14 Apr 2020 16:19:56 +0000
To: public-dxwg-wg@w3.org
Message-ID: <issues.opened-599695732-1586881194-sysbot+gh@w3.org>
rawmatt has just created a new issue for https://github.com/w3c/dxwg:

== foaf:page, not foaf:homepage ==
As an implementer, the [alignment with Schema.org](https://www.w3.org/TR/vocab-dcat-2/#dcat-sdo) is very useful. I use the [published alignment](https://w3c.github.io/dxwg/dcat/rdf/dcat-schema.ttl) with OWL-RL to infer my data catalog into it's SDO equivalents. This is useful for activities, such as driving [Google Dataset Search](https://datasetsearch.research.google.com).

I disagree with one mapping in the alignment, that for foaf:homepage.
  owl:equivalentProperty schema:url ;
The problem with using this relationship is that it is [symmetric](https://www.w3.org/TR/owl2-syntax/#Symmetric_Object_Properties). I agree that every foaf:homepage is also a schema:url, but the reverse is untrue. There are many schema:url that are not foaf:homepage.

schema:url is such a broadly defined property, far broader than foaf:homepage. These properties have very different breadth of applicability, and shouldn't be marked as equivalent.

The problem is that with this DCAT alignment, everywhere I have a schema:url, I am now seeing a foaf:homepage being inferred. And I have many schema:urls, and few of them are homepages.

The inference rules relevant here are prp-eqp1 and prp-eqp2.

The best mapping in the FOAF vocabulary to schema:url, is foaf:page. The definitions are very similar between schema:url and foaf:page. I propose changing the DCAT alignment to: 
  owl:equivalentProperty schema:url ;

This would achieve the desired result of mapping foaf:homepage to schema:url, but not the reverse. This is because [foaf:homepage](http://xmlns.com/foaf/spec/#term_homepage) is defined in FOAF as a sub-property of [foaf:page](http://xmlns.com/foaf/spec/#term_page).

DCAT would still contain foaf:homepage. The mapping to schema:url would now be through the super-property relationship from foaf:homepage to foaf:page, and then through the equivalence to schema:url.

Please view or discuss this issue at https://github.com/w3c/dxwg/issues/1231 using your GitHub account
Received on Tuesday, 14 April 2020 16:20:02 UTC

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