What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_4, x_4 is a sailor. For all x_4, if x_4 were a sailor, then x_4 is a bartender. For all x_4, if x_4 were a bartender, then x_4 is a sailor.
For all x_4, x_4 is a bartender. For all x_4, x_4 is a sailor if and only if x_4 is a bartender. For all x_4, x_4 is a bartender if and only if x_4 is a sailor.