Consider the following premises. p_11 <-> R_17(a_17). p_11. forall x_17: ~R_17(x_17). Can we infer r_3 from them? If possible, name the inference rules being used at each step.
 From forall x_17: ~R_17(x_17) we can infer ~R_17(a_17) via universal instantiation. From p_11 <-> R_17(a_17), ~R_17(a_17) we can infer ~p_11 via biconditional elimination. From ~p_11 we can infer ~p_11 or r_3 via addition. Finally, from ~p_11 or r_3, p_11 we can infer r_3 via disjunctive syllogism. Therefore, the answer is yes. Notice, however, that the premises were contradictory, so we can infer anything from them.