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: p or ~s. s <-> p. ~s.
s -> p can be inferred via the rewriting rule. s -> p can be inferred via the biconditional elimination rule. p -> s can be inferred via the biconditional elimination rule. ~p can be inferred via the biconditional elimination rule.