Consider the following premises. R(c_4) or ~W_3(c_4). forall z_3: R(z_3) -> W_3(z_3). Can we infer W_3(c_4) <-> R(c_4) from them? If possible, name the inference rules being used at each step.
 From forall z_3: R(z_3) -> W_3(z_3) we can infer R(c_4) -> W_3(c_4) via universal instantiation. From R(c_4) or ~W_3(c_4) we can infer W_3(c_4) -> R(c_4) via rewriting. Finally, from W_3(c_4) -> R(c_4), R(c_4) -> W_3(c_4) we can infer W_3(c_4) <-> R(c_4) via biconditional introduction. Therefore, the answer is yes.