What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Michael is climbing a mountain if and only if Joseph is an astronaut. It is sunny or Michael is climbing a mountain. It is sunny if and only if Joseph is an astronaut.
If Michael climbs a mountain, then Joseph is an astronaut. If it is sunny, then Joseph is an astronaut. If Joseph were an astronaut, then Michael is climbing a mountain. If Joseph were an astronaut, then it is sunny.