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 <-> s_2. w or ~s_2. p -> s. ~w.
~s_2 can be inferred via the disjunctive syllogism rule. s_2 -> w can be inferred via the rewriting rule. s -> s_2 can be inferred via the biconditional elimination rule. s_2 -> s can be inferred via the biconditional elimination rule.