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: forall x_14: P_14(x_14). P_14(b) <-> u.
P_14(b) -> u can be inferred via the biconditional elimination rule. u -> P_14(b) can be inferred via the biconditional elimination rule.