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: ~s. s <-> r_2. ~q_7 -> q. r_2 <-> q_7.
s -> r_2 can be inferred via the biconditional elimination rule. r_2 -> q_7 can be inferred via the biconditional elimination rule. r_2 -> s can be inferred via the biconditional elimination rule. q_7 -> r_2 can be inferred via the biconditional elimination rule. ~r_2 can be inferred via the biconditional elimination rule.