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Re: [dxwg] Use of dct:type with both Class and Concept

From: Jakub Klímek via GitHub <sysbot+gh@w3.org>
Date: Tue, 28 Aug 2018 10:15:49 +0000
To: public-dxwg-wg@w3.org
Message-ID: <issue_comment.created-416529796-1535451343-sysbot+gh@w3.org>
@makxdekkers 

> I am just wondering why you think it is 'unintended' that an instance of skos:Concept used to classify datasets would also be an instance of rdfs:Class

OK, let me try to explain it another way. Let's say I have my own `skos:ConceptScheme` for classifying datasets. There are `skos:Concepts` for, e.g. genres. [According to SKOS](https://www.w3.org/TR/skos-reference/#L896), it is intentionally undefined whether those concepts are also `rdfs:Class`es or not, i.e. it is up to the publisher. So, since it is my `skos:ConceptScheme`, I decide I do not want them to be `rdfs:Class`es.

Now, I want to use those concepts to classify my datasets using DCAT. I find `dct:type`, since that is the property DCAT users will expect for this according to its description in DCAT, and I want them to be able to understand my data. But I still have no intention of my concepts to become `rdfs:Class`es. However, by using `dct:type` to link to them, I effectively made them `rdfs:Class`es thanks to `dct:type`s `rdfs:range` definition. 

My question here is: *"Why do my concepts have to become `rdfs:Class`es just because I want to use them with DCAT recommended property for genre classification?"* Classifying dataset with a genre should keep the genre intact, and not imply something about it that was not there before I used it.

The bottom line here I think is, if I wanted the genre concepts to be used as classes, I would have made them classes myself, explicitly, and then probably used them with `rdf:type`, not `dct:type`.

> Could it be solved with a warning

Well, a warning is the least I would expect there. But the question is why there should be something that needs a usage warning? Do we need the property for classification to be `dct:type` so bad?

> I don't think there was an explicit intention at DCMI to exclude the use of skos:Concept as object for dct:type

And I do not to say that it is/should be excluded to use skos:Concepts as objects for `dct:type`.
I say that it unintentionally entails information about the used concepts that might not have been there before.
If the concepts were also classes before usage, everything is fine.
But if they were not classes before usage, they become ones ***just because*** they were used with DCAT and `dct:type`. That I think will not be the intention of users of DCAT, and often enough they will not be able to forsee the effects of this, nor should they.

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Received on Tuesday, 28 August 2018 10:15:50 UTC

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