public static IList closure(IList rel1) { Type resultType = rel1.getType().closure(); // will throw exception if not binary and reflexive IList tmp = rel1; int prevCount = 0; ShareableValuesHashSet addedTuples = new ShareableValuesHashSet(); while (prevCount != tmp.length()) { prevCount = tmp.length(); IList tcomp = compose(tmp, tmp); IListWriter w = List.createListWriter(resultType.getElementType()); for (IValue t1 : tcomp) { if (!tmp.contains(t1)) { if (!addedTuples.contains(t1)) { addedTuples.add(t1); w.append(t1); } } } tmp = tmp.concat(w.done()); addedTuples.clear(); } return tmp; }