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_4 and u_2. w -> t. p_4 <-> w.
p_4 can be inferred via the simplification rule. u_2 can be inferred via the simplification rule. p_4 -> w can be inferred via the biconditional elimination rule. w -> p_4 can be inferred via the biconditional elimination rule.