Consider the following premises. forall x_10: U_4(x_10) -> S_10(x_10). U_4(a_10) or ~S_10(a_10). Can we infer ~(S_10(a_10) <-> U_4(a_10)) from them?
 From forall x_10: U_4(x_10) -> S_10(x_10) we can infer U_4(a_10) -> S_10(a_10). From U_4(a_10) or ~S_10(a_10) we can infer S_10(a_10) -> U_4(a_10). Finally, from S_10(a_10) -> U_4(a_10), U_4(a_10) -> S_10(a_10) we can infer S_10(a_10) <-> U_4(a_10), which contradicts ~(S_10(a_10) <-> U_4(a_10)). Therefore, the answer is no.