What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x: ~U_1(x). forall x: U_1(x) -> S(x). p <-> S(f_2). forall x: S(x) -> U_1(x).
p -> S(f_2). S(f_2) -> p. forall x: ~S(x). forall x: U_1(x) <-> S(x). forall x: S(x) <-> U_1(x).