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_12: S(x_12) <-> S_12(x_12). S(a_12) -> p. p -> S_12(a_12).
S(a_12) -> S_12(a_12) can be inferred via the transitivity rule. forall x_12: S(x_12) -> S_12(x_12) can be inferred via the universal biconditional elimination rule. forall x_12: S_12(x_12) -> S(x_12) can be inferred via the universal biconditional elimination rule.