What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x, if x goes running, then x is taking a plane. There is at least one x for which if x takes a plane, then x is running.
There is at least one x for which x will take a plane if and only if x will go running. There is at least one x for which x will go running if and only if x will take a plane.