schema:url equivalent to foaf:page

[rawmatt]

Adds an alignment between schema:url and foaf:page.

I use DCAT, Schema.org, and FOAF to describe my dataset products. The alignment between Schema.org and FOAF currently exists in DCAT https://github.com/w3c/dxwg/blob/c58b79313c10be2ec13c32d8296098fbc050d216/dcat/rdf/dcat-schema.ttl#L223, not in Schema.org.

The effect is that even though I may have no usage of DCAT vocabulary, whether I include the DCAT definitions or not affects my data described using Schema.org.

I believe the alignment between FOAF and Schema.org is better served being in Schema.org, rather than being in a third vocabulary.

[stain]

Using owl:equivalentProperty means (at least in OWL) you also get the inference that the range of http://schema.org/url is a foaf:Document however https://schema.org/url does not require the URL to be (pointing at) a document. For instance the URL can be a #section within a page, a JPEG picture, a mp4 video, a mp3 podcast or a web form.

With the OWL inference you also get along the inverse foaf:topic which is a bit strong implication for what may not be a document.

Personally I would think a more natural mapping of topic/page would be:

• foaf:page == https://schema.org/subjectOf
• foaf:topic == https://schema.org/about (both inverses of above)

Then we also have the more specific subproperties on both sides:

• foaf:primaryTopic == https://schema.org/mainEntity
• foaf:isPrimaryTopicOf == https://schema.org/mainEntityOfPage

To be honest I am not sure what is the originally purpose of http://schema.org/url although its ambiguousness have always came in handy when @id is too strong and subjectOf too documenty - it's like a generic <a href=""> without a rel and without having to say anything more about the URL.

I guess @danbri as original FOAF author might have views!

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