private boolean isProperSubset (List<String> subset, List<String> superset) {
		
		if (subset.size() >= superset.size())
			return false;
		
		Iterator<String> itr = subset.iterator();
		while (itr.hasNext()) {
			String element = itr.next();
			if (!superset.contains(element))
				return false;
		}
		
		return true;
		
	}