Consider the following premises. forall x_10: R_10(x_10) or S_10(x_10). w -> S_10(a_10). R_10(a_10) -> w. S_10(a_10) -> w. Can we infer ~w from them?
 From forall x_10: R_10(x_10) or S_10(x_10) we can infer R_10(a_10) or S_10(a_10). From w -> S_10(a_10), S_10(a_10) -> w we can infer w <-> S_10(a_10). From w <-> S_10(a_10) we can infer S_10(a_10) -> w. Finally, from R_10(a_10) -> w, S_10(a_10) -> w, R_10(a_10) or S_10(a_10) we can infer w, which contradicts ~w. Therefore, the answer is no.