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 w. s_1 <-> q. p or q. ~s_1.
q or w can be inferred via the resolution rule. s_1 -> q can be inferred via the biconditional elimination rule. q -> s_1 can be inferred via the biconditional elimination rule. ~q can be inferred via the biconditional elimination rule.