What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: q_1 -> q. q -> ~p_3. q -> q_1. p_3.
~q can be inferred via the modus tollens rule. q_1 -> ~p_3 can be inferred via the transitivity rule. q_1 <-> q can be inferred via the biconditional introduction rule. q <-> q_1 can be inferred via the biconditional introduction rule.