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 -> q. q_11 -> q. q_11 -> p_4. q -> q_11.
p -> q_11 can be inferred via the transitivity rule. q -> p_4 can be inferred via the transitivity rule. q_11 <-> q can be inferred via the biconditional introduction rule. q <-> q_11 can be inferred via the biconditional introduction rule.