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 z_4: ~P_1(z_4). forall z_4: U(z_4) <-> Q_3(z_4). forall z_4: Q_3(z_4) <-> P_3(z_4). exists z_4: P_1(z_4) <-> P_3(z_4).
forall z_4: U(z_4) -> Q_3(z_4) can be inferred via the universal biconditional elimination rule. forall z_4: Q_3(z_4) -> P_3(z_4) can be inferred via the universal biconditional elimination rule. exists z_4: P_1(z_4) -> P_3(z_4) can be inferred via the existential biconditional elimination rule. forall z_4: Q_3(z_4) -> U(z_4) can be inferred via the universal biconditional elimination rule. forall z_4: P_3(z_4) -> Q_3(z_4) can be inferred via the universal biconditional elimination rule. exists z_4: P_3(z_4) -> P_1(z_4) can be inferred via the existential biconditional elimination rule. exists z_4: ~P_3(z_4) can be inferred via the existential biconditional elimination rule.