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 -> p_8. p_8 -> s. s -> p_8.
s <-> p_8 can be inferred via the biconditional introduction rule. p_8 <-> s can be inferred via the biconditional introduction rule. p_8 <-> s can be inferred via the biconditional introduction rule. s <-> p_8 can be inferred via the biconditional introduction rule.