public void delete(ArrayList<Predicate> pl){
		for(int i = 0; i < pl.size(); i++){ // for each predicate
			Predicate p = pl.get(i);
			
			boolean found = false;
			int j = 0;
			while(j < predList.size() && !found){
				found = predList.get(j).equalsPredicate(p);
				j++;
			}
			
			if(found){
				predList.remove(j-1);
			}	
		}
	}