Consider the following premises. q -> u. u -> W_2(c). forall x_20: W_2(x_20) -> S_20(x_20). q <-> S_20(c). Can we infer W_2(c) <-> S_20(c) from them?
 From forall x_20: W_2(x_20) -> S_20(x_20) we can infer W_2(c) -> S_20(c). From q -> u, u -> W_2(c) we can infer q -> W_2(c). From q <-> S_20(c) we can infer S_20(c) -> q. From S_20(c) -> q, q -> W_2(c) we can infer S_20(c) -> W_2(c). Finally, from W_2(c) -> S_20(c), S_20(c) -> W_2(c) we can infer W_2(c) <-> S_20(c). Therefore, the answer is yes.