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: p_2 -> q. q_7. q -> ~q_7. q -> p_2. q_2 -> p_2.
~q can be inferred via the modus tollens rule. p_2 -> ~q_7 can be inferred via the transitivity rule. q_2 -> q can be inferred via the transitivity rule. p_2 <-> q can be inferred via the biconditional introduction rule. q <-> p_2 can be inferred via the biconditional introduction rule.