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 -> r_11. ~r_11. p_8 <-> p. p -> s.
~s can be inferred via the modus tollens rule. p -> r_11 can be inferred via the transitivity rule. p_8 -> p can be inferred via the biconditional elimination rule. p -> p_8 can be inferred via the biconditional elimination rule.