code: public static boolean isCompatible(TreeWitness tw1, TreeWitness tw2) {
  		Set<Term> commonTerms = new HashSet<>(tw1.getDomain());
  		commonTerms.retainAll(tw2.getDomain());
  		if (!commonTerms.isEmpty()) {
  			if (!tw1.getRoots().containsAll(commonTerms) || !tw2.getRoots().containsAll(commonTerms))
  				return false;
  		}
  		return true;
  	}
docs: boolean isCompatibleWith(TreeWitness tw1, TreeWitness tw2)
  
  tree witnesses are consistent iff their domains intersect on their **common** roots
  
  @param tw1: a tree witness
  @return true if tw1 is compatible with the given tree witness