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 -> q. u_2 <-> p. ~u_2.
u_2 -> p can be inferred via the biconditional elimination rule. p -> u_2 can be inferred via the biconditional elimination rule. ~p can be inferred via the biconditional elimination rule.