What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If it is cold, then it is raining. It is cold or Michael is taking a plane. David is not fast. David is fast or Jennifer is not writing a letter. If Michael takes a plane, then it is raining.
Jennifer is not writing a letter. If Jennifer writes a letter, then David is fast. It is raining.