Consider the following premises. u -> q_24. t -> R_4(j). q_24 -> u. forall y: ~R_4(y). ~u. Can we infer q_24 from them? If possible, name the inference rules being used at each step.
 From u -> q_24, q_24 -> u we can infer u <-> q_24 via biconditional introduction. From forall y: ~R_4(y) we can infer ~R_4(j) via universal instantiation. Finally, from u <-> q_24, ~u we can infer ~q_24 via biconditional elimination, which contradicts q_24. Therefore, the answer is no.