The sentence
Explicit sub-properties of the abstract relation, relation and failure properties must be used, the choice depending on the subclass of Rule in question.
Should have been
Explicit sub-properties of the abstract relation, function and failure properties must be used, the choice depending on the subclass of Rule in question.
In the section https://www.w3.org/TR/odrl-model/#rule
The sentence Explicit sub-properties of the abstract relation, relation and failure properties must be used, the choice depending on the subclass of Rule in question.
Should have been Explicit sub-properties of the abstract relation, function and failure properties must be used, the choice depending on the subclass of Rule in question.