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_6 <-> s. w -> q_6. w.
q_6 can be inferred via the modus ponens rule. q_6 -> s can be inferred via the biconditional elimination rule. s -> q_6 can be inferred via the biconditional elimination rule.