Consider the following premises. S_14(a_14) -> u. w or R_14(a_14). w -> S_14(a_14). forall x_14: R_14(x_14) -> S_14(x_14). Can we infer ~u from them? If possible, name the inference rules being used at each step.
 From forall x_14: R_14(x_14) -> S_14(x_14) we can infer R_14(a_14) -> S_14(a_14) via universal instantiation. From w -> S_14(a_14), R_14(a_14) -> S_14(a_14), w or R_14(a_14) we can infer S_14(a_14) via disjunction elimination. Finally, from S_14(a_14) -> u, S_14(a_14) we can infer u via modus ponens, which contradicts ~u. Therefore, the answer is no.