protected OWLAxiom trTypedefClause(@Nonnull OWLObjectProperty p,
String tag, @Nonnull Clause clause) {
OWLAxiom ax = null;
Object v = clause.getValue();
Set<OWLAnnotation> annotations = trAnnotations(clause);
OboFormatTag tagConstant = OBOFormatConstants.getTag(tag);
if (tagConstant == OboFormatTag.TAG_IS_A) {
ax = fac.getOWLSubObjectPropertyOfAxiom(p,
trObjectProp((String) v), annotations);
} else if (tagConstant == OboFormatTag.TAG_RELATIONSHIP) {
IRI relId = oboIdToIRI((String) clause.getValue());