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: ~r_4. w_3 <-> S_2(a_7). forall z_4: U(z_4) <-> S_2(z_4). w_3 <-> r_4.
w_3 -> S_2(a_7) can be inferred via the biconditional elimination rule. w_3 -> r_4 can be inferred via the biconditional elimination rule. S_2(a_7) -> w_3 can be inferred via the biconditional elimination rule. r_4 -> w_3 can be inferred via the biconditional elimination rule. ~w_3 can be inferred via the biconditional elimination rule. forall z_4: U(z_4) -> S_2(z_4) can be inferred via the universal biconditional elimination rule. forall z_4: S_2(z_4) -> U(z_4) can be inferred via the universal biconditional elimination rule.