public static Proposition buildImpliesProposition(Cons tree) {
    Logic.verifyNumberOfPropositionArguments(tree, 2);
    { Stella_Object tailarg = Logic.evaluateTerm(tree.rest.value);
      Stella_Object headarg = Logic.evaluateTerm(tree.rest.rest.value);

      return (Logic.createImpliesProposition(tailarg, headarg));
    }
  }