How to relate a SKOS concept as the union of two other concepts

Question

I am defining mappings between two concepts schemes, and have the following situation:

wp20:in a skos:Concept ;
    skos:scopeNote "A preposition or subordinating conjunction"@en .

pos:conjunction a skos:Concept .
pos:preposition a skos:Concept .

What I want to do is describe the scope note as RDF metadata. For example, something like:

wp20:in skos:exactMatch [
    a owl:unionOf ;
    skos:broadMatch pos:conjunction ;
    skos:exactMatch pos:preposition
] .

The above does not work as the domain and range of skos:*Match are skos:Concept objects (so it is also not possible to use skos:Collection types either). Additionally, the SKOS Mapping vocabulary is deprecated and has not been completed (although some of the mapping properties have been moved into SKOS Core).

How do I describe this relationship using SKOS vocabulary?

Answer 1

It seems from your comments that what you really want to state is the wp20:in is either a broader match of pos:conjunction or an exact match of pos:preposition. In that case, the representation can be:

wp20:in skos:broadMatch pos:conjunction ;
        skos:exactMatch pos:preposition .

This basically states that instances of wp20:in is "A preposition or subordinating conjunction", with the appropriate match relationship. That seems to fit your requirements.

Answer 2

First, note that the SKOS specification is freely available online. I'm not much of a SKOS user, but if I encounter a question about SKOS, that's where I look first. Some important notes that suggest that what you're looking for might not attainable in SKOS include:

3.5.1. SKOS Concepts, OWL Classes and OWL Properties

Other than the assertion that skos:Concept is an instance of owl:Class, this specification does not make any additional statement about the formal relationship between the class of SKOS concepts and the class of OWL classes. The decision not to make any such statement has been made to allow applications the freedom to explore different design patterns for working with SKOS in combination with OWL.

I point that out just to say that SKOS concepts aren't the same thing as OWL classes, so saying that an SKOS concept is an exact match for an OWL class might be a bit unusual.

If it is possible, it looks like it would be somewhere in §8. Semantic Relations, which specifies the kinds of relations that can exist among concepts. It appears that the relationships that you can have are:

• skos:semanticRelation
• skos:broader
• skos:narrower
• skos:related
• skos:broaderTransitive
• skos:narrowerTransitive

Based on that list, I think that perhaps the best you could do in pure SKOS would be something like:

wp20:in skos:narrower pos:conjunction ,
                      pos:preposition .

which doesn't, I think, exactly capture what you want, but might be close enough.