* @return the oWL class expression
*/
public OWLClassExpression trRel(@Nonnull String relId,
@Nonnull String classId, @Nonnull Collection<QualifierValue> quals) {
Frame relFrame = obodoc.getTypedefFrame(relId);
OWLObjectPropertyExpression pe = trObjectProp(relId);
OWLClassExpression ce = trClass(classId);
assert pe != null;
assert ce != null;
Integer exact = getQVInt("cardinality", quals);
Integer min = getQVInt("minCardinality", quals);