Consider the following premises. w <-> W(f). forall z_3: ~W(z_3). w. Can we infer q from them? If possible, name the inference rules being used at each step.
 From forall z_3: ~W(z_3) we can infer ~W(f) via universal instantiation. From w <-> W(f), ~W(f) we can infer ~w via biconditional elimination. From ~w we can infer ~w or q via addition. Finally, from ~w or q, w we can infer q via disjunctive syllogism. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.