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 -> p. p -> ~s. s. p -> q_6.
~p can be inferred via the modus tollens rule. q_6 -> ~s can be inferred via the transitivity rule. q_6 <-> p can be inferred via the biconditional introduction rule. p <-> q_6 can be inferred via the biconditional introduction rule.