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: exists x_13: P(x_13) -> Q_7(x_13). forall x_13: Q_5(x_13) <-> R_7(x_13). forall x_13: Q_7(x_13) -> R_7(x_13). forall x_13: ~P_13(x_13). forall x_13: P_13(x_13) or P(x_13).
exists x_13: P(x_13) -> R_7(x_13) can be inferred via the existential transitivity rule. forall x_13: P(x_13) can be inferred via the universal disjunctive syllogism rule. forall x_13: Q_5(x_13) -> R_7(x_13) can be inferred via the universal biconditional elimination rule. forall x_13: R_7(x_13) -> Q_5(x_13) can be inferred via the universal biconditional elimination rule.