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_6: Q(x_6) -> R_3(x_6). exists x_6: R_3(x_6) -> Q(x_6). forall x_6: R(x_6) -> R_3(x_6). forall x_6: R(x_6) or Q(x_6).
exists x_6: R(x_6) -> Q(x_6) can be inferred via the existential transitivity rule. forall x_6: R_3(x_6) can be inferred via the universal disjunction elimination rule. exists x_6: R_3(x_6) <-> Q(x_6) can be inferred via the existential biconditional introduction rule. exists x_6: Q(x_6) <-> R_3(x_6) can be inferred via the existential biconditional introduction rule.