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_3: Q_1(x_3) -> S_2(x_3). Q_1(a_7) <-> q. forall x_3: S_2(x_3) -> Q_1(x_3). ~q.
Q_1(a_7) -> q can be inferred via the biconditional elimination rule. q -> Q_1(a_7) can be inferred via the biconditional elimination rule. ~Q_1(a_7) can be inferred via the biconditional elimination rule. forall x_3: Q_1(x_3) <-> S_2(x_3) can be inferred via the universal biconditional introduction rule. forall x_3: S_2(x_3) <-> Q_1(x_3) can be inferred via the universal biconditional introduction rule.