What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Michael is taking a plane if and only if Sarah is playing a game. Elisabeth is cooking if and only if Sarah is playing a game. Sarah is not a doctor. Elisabeth is cooking if and only if it is snowing. Michael is taking a plane if and only if Sarah is a doctor.
If Michael takes a plane, then Sarah is playing a game. If Elisabeth cooks, then Sarah is playing a game. If Elisabeth cooks, then it is snowing. If Michael takes a plane, then Sarah is a doctor. If Sarah plays a game, then Michael is taking a plane. If Sarah plays a game, then Elisabeth is cooking. If it snows, then Elisabeth is cooking. If Sarah were a doctor, then Michael is taking a plane. Michael is not taking a plane.