How can I create an owl:intersectionOf two owl:Classes? - sparql

Question

For a school exercise, I have an RDF file and an OWL file.
There is an owl:Class Lecturer and an owl:Class Researcher. The intersection of both should be a Professor. I have put my RDF and OWL file below.
Problem is: when I do my query, no resource is of type Professor, while in the RDF file we can see that Laura should be a Professor.
Reduced version of rdf file:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE rdf:RDF [
<!ENTITY humans "http://www.inria.fr/2007/09/11/humans.rdfs">
<!ENTITY xsd "http://www.w3.org/2001/XMLSchema#"> ]>
<rdf:RDF
xmlns:rdf ="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns:xsd ="&xsd;"
xmlns ="&humans;#"
xml:base ="&humans;-instances" >
<Person rdf:ID="Laura">
<name>Laura</name>
</Person>
<Lecturer rdf:about="#Laura"/>
<Researcher rdf:about="#Laura">
<name>Laura</name>
</Researcher>
</rdf:RDF>
Reduced version of owl file:
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
xmlns="http://www.w3.org/2000/01/rdf-schema#"
xml:base="http://www.inria.fr/2007/09/11/humans.rdfs"
xmlns:owl="http://www.w3.org/2002/07/owl#">
<owl:Class rdf:ID="Person">
</owl:Class>
<owl:Class rdf:ID="Lecturer">
<subClassOf rdf:resource="#Person"/>
</owl:Class>
<owl:Class rdf:ID="Researcher">
<subClassOf rdf:resource="#Person"/>
</owl:Class>
<owl:Class rdf:id="Professor">
<owl:intersectionOf rdf:parseType="Collection">
<owl:Class rdf:about="#Lecturer"/>
<owl:Class rdf:about="#Researcher"/>
</owl:intersectionOf>
</owl:Class>
</rdf:RDF>
The query I used was the defautl query:
select * where {
?x ?p ?y
}
But what I actually would expect to do is the following:
select * where {
?x a <http://www.inria.fr/2007/09/11/humans.rdfs#Professor>
}
I did look at this answer: Why do we need to use rdf:parseType="Collection" with owl:intersectionOf? but I don't understand in which way it should be used for my specific problem.
I hope somebody can help. By the way, it's my first post here, so let me know if something's missing.

Answer 1

Paraphrased from comments by #stanislav-kralin:
Use correct capitalization of rdf:ID (not rdf:id), and enable "OWL-Max" reasoning when loading your RDF into GraphDB.