Consider the following premises. forall x_11: W(x_11) <-> S_11(x_11). ~W(a_11). Can we infer ~S_11(a_11) or t from them?
 From forall x_11: W(x_11) <-> S_11(x_11) we can infer W(a_11) <-> S_11(a_11). From W(a_11) <-> S_11(a_11), ~W(a_11) we can infer ~S_11(a_11). Finally, from ~S_11(a_11) we can infer ~S_11(a_11) or t. Therefore, the answer is yes.