What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? R_13(a_13) <-> s_3. forall x_13: R_13(x_13) or S_13(x_13). ~s. s_3 -> s.
~s_3. R_13(a_13) -> s_3. s_3 -> R_13(a_13).