What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If John writes a letter, then John is not fast. If John were not fast, then John is writing a letter. Patricia is not a soldier. Patricia is a soldier if and only if John is fast.
John is writing a letter if and only if John is not fast. John is not fast if and only if John is writing a letter. If Patricia were a soldier, then John is fast. If John were fast, then Patricia is a soldier. John is not fast.