What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? ~w_2. forall x_19: R_19(x_19) -> S_19(x_19). S_19(a_19) <-> w_2.
S_19(a_19) -> w_2. w_2 -> S_19(a_19). ~S_19(a_19).