I tried loading ontology/math.ttl locally but protege generated errors while loading.

How to reproduce

Load the ontology locally with Protege 5.6.x

Suggested fix

To fix this I found out that the rdfs and rdf imports should be added since AttributionList, ObjectList, VariableList are of type rdfs:class.

<http://openmath.org/vocab/math>
  rdf:type owl:Ontology ;              
  owl:imports <http://www.w3.org/2000/01/rdf-schema> ;
  owl:imports <http://www.w3.org/1999/02/22-rdf-syntax-ns> .