else if (rest==null) return c;
if (cls==null) cls = xs.ont.createClass(uri);
if (cls!=null) cls.addProperty(RDFS.subClassOf,OWL.Thing);
// restrictions are required internally to define the class, if not by the caller
if (rest==null && (uri!=null || (uri==null && createAnon))) rest = new Restrictions();
// declare local elements & attributes, extensions & restrictions (for subclassing below)
if (sequence!=null) sequence.toOWL(rest, 1, 1, ctx);
if (choice!=null) choice.toOWL(rest, 1, 1, ctx);