Constraints on a property in a SKOS hierarchy

Dear all,

 

I would like to to the following:

 

1.	Define a property "ex:myProperty" for a skos:Concept. 
2.	In a given SKOS taxonomy, the following constraint should be
formulated: for the taxonomy, the property should appear zero or more times
in one "branch" of the taxonomy.

 

The following would be a valid SKOS RDF graph:

 

example:animal a skos:Concept; ex:myProperty "some value".

example:bird a skos:Concept; skos:broader example:animal.

 

The following would be a non-valid SKOS RDF graph, since example:bird is
connected to another concept (example:animal) that already has
ex:myProperty:

 

example:animal a skos:Concept; ex:myProperty "some value".

example:bird a skos:Concept; skos:broader example:animal; ex:myProperty
"some value".

 

How would I formulate 2) in SHACL? 

 

Regards

 

Felix