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_4 or ~s_3. ~u_2. p_16 <-> u_2. ~p_16 -> s_4.
s_3 -> s_4 can be inferred via the rewriting rule. p_16 -> u_2 can be inferred via the biconditional elimination rule. u_2 -> p_16 can be inferred via the biconditional elimination rule. ~p_16 can be inferred via the biconditional elimination rule.