Consider the following premises. w_1 -> r. ~R_21(a_21). ~r. forall x_21: R_21(x_21) or S_21(x_21). Can we infer ~S_21(a_21) from them?
 From forall x_21: R_21(x_21) or S_21(x_21) we can infer R_21(a_21) or S_21(a_21). Finally, from R_21(a_21) or S_21(a_21), ~R_21(a_21) we can infer S_21(a_21), which contradicts ~S_21(a_21). Therefore, the answer is no.