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_13. s. s_2 <-> q_13.
q_13 and s can be inferred via the conjunction rule. s and q_13 can be inferred via the conjunction rule. s_2 -> q_13 can be inferred via the biconditional elimination rule. q_13 -> s_2 can be inferred via the biconditional elimination rule.