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_1: Q(x_1) <-> U(x_1). Q(b) -> U(b).
forall x_1: Q(x_1) -> U(x_1) can be inferred via the universal biconditional elimination rule. forall x_1: U(x_1) -> Q(x_1) can be inferred via the universal biconditional elimination rule.