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_1 <-> q. w or ~q_1. ~w.
~q_1 can be inferred via the disjunctive syllogism rule. q_1 -> w can be inferred via the rewriting rule. q_1 -> q can be inferred via the biconditional elimination rule. q -> q_1 can be inferred via the biconditional elimination rule.