private static SimTupleset convert(Object object) throws Err {
if (!(object instanceof A4TupleSet)) throw new ErrorFatal("Unexpected type error: expecting an A4TupleSet.");
A4TupleSet s = (A4TupleSet)object;
if (s.size()==0) return SimTupleset.EMPTY;
List<SimTuple> list = new ArrayList<SimTuple>(s.size());
int arity = s.arity();
for(A4Tuple t: s) {
String[] array = new String[arity];
for(int i=0; i<t.arity(); i++) array[i] = t.atom(i);
list.add(SimTuple.make(array));
}