Correct way to describe inferred property with OWL and RDF

I am trying to write an inference rule using OWL.

Given the following:

A document is classified as having a category - let's say "Contract Law"
There is a parent category "Law", with "Contract Law" as a sub-category
I would like to infer that the document is also classified with "Law"

Statements:

@prefix : <http://example.com/> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix owl: <http://www.w3.org/2002/07/owl#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .

:Document rdf:type owl:Class .
:Category rdf:type owl:Class .

:documentHasCategory rdf:type owl:ObjectProperty ;
                rdfs:domain :Document ;
                rdfs:range :Category .

:hasSubCategory rdf:type owl:ObjectProperty ;
                rdfs:domain :Category ;
                rdfs:range :Category .

:category1 rdf:type :Category ;
      rdfs:label "Law" ;
      :hasSubCategory :category2 .

:category2 rdf:type :Category ;
      rdfs:label "Contract Law".

:doc1 rdf:type :Document ;
     :documentHasCategory :category2 .

How should I write an inference statement to add the category of "Law" to the document? I tried:

:inferredCategory rdf:type owl:ObjectProperty ;
                 rdfs:domain :Document ;
                 rdfs:range :Category ;
                 owl:propertyChainAxiom ( :documentHasCategory :hasSubCategory ) .

But I'm not seeing any inferred statements (I'm using GraphDB).

Is owl:propertyChainAxiom the correct way to approach this? Have I got my turtle syntax wrong?

Solution

I wasn't respecting the direction of the hasSubCategory predicate, so nothing actually matches the propertyChain rule.

Defining the inference like this works just fine:

:hasParentCategory rdf:type owl:ObjectProperty ;
    owl:inverseOf :hasChildCategory .

:documentHasInferredCategory rdf:type owl:ObjectProperty ;
                rdfs:domain :Document ;
                rdfs:range :Category ;
                owl:propertyChainAxiom ( :documentHasCategory :hasParentCategory ) .