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: U_1(a_12) <-> S_2(a_12). forall x: S_2(x) -> U_1(x).
U_1(a_12) -> S_2(a_12) can be inferred via the biconditional elimination rule. S_2(a_12) -> U_1(a_12) can be inferred via the biconditional elimination rule.