*/
static class Ref<T> extends Forest<T> {
public HashSet<GSS.Phase.Node> parents = new HashSet<GSS.Phase.Node>();
+ public boolean contains(Forest f) {
+ return hp.contains(f);
+ }
public boolean ambiguous() {
if (hp.size()==0) return false;
if (hp.size()==1) return hp.iterator().next().ambiguous();