public static boolean isFormulaUnSAT(Vector<Clause> clauses) {
		if(SsatSolver.DEBUG) System.out.println("Seeing if formula is UNSAT");
		for(int i = 0; i < clauses.size(); i++) {
			Clause c = clauses.get(i);
			//try to find one clause that is  UnSAT
			if(c.isUnsatisfied()) { 
				if(SsatSolver.DEBUG) System.out.println("Clause " + i + " is UNSAT");
				return true;
			}
		}
		return false;
	}