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: R_1(z) <-> R_2(z). ~R_1(a_7). w <-> R_2(a_7).
w -> R_2(a_7) can be inferred via the biconditional elimination rule. R_2(a_7) -> w can be inferred via the biconditional elimination rule. forall z: R_1(z) -> R_2(z) can be inferred via the universal biconditional elimination rule. forall z: R_2(z) -> R_1(z) can be inferred via the universal biconditional elimination rule.