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_4 <-> ~r_2. ~p_12. p_12 <-> r_2.
p_4 -> ~r_2 can be inferred via the biconditional elimination rule. p_12 -> r_2 can be inferred via the biconditional elimination rule. ~r_2 -> p_4 can be inferred via the biconditional elimination rule. r_2 -> p_12 can be inferred via the biconditional elimination rule. ~r_2 can be inferred via the biconditional elimination rule.