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: ~q_3 or p_4. ~u. u <-> s_2. q_3 or s_2.
s_2 or p_4 can be inferred via the resolution rule. u -> s_2 can be inferred via the biconditional elimination rule. s_2 -> u can be inferred via the biconditional elimination rule. ~s_2 can be inferred via the biconditional elimination rule.