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_1: Q_1(x_1) -> R_3(x_1). forall x_1: R_3(x_1) -> Q_1(x_1). exists x_1: ~Q_1(x_1).
exists x_1: ~R_3(x_1) can be inferred via the existential modus tollens rule. forall x_1: Q_1(x_1) <-> R_3(x_1) can be inferred via the universal biconditional introduction rule. forall x_1: R_3(x_1) <-> Q_1(x_1) can be inferred via the universal biconditional introduction rule.