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 cooks, then x is writing a letter. There is at least one x for which if x writes a letter, then x is cooking.
There is at least one x for which x will write a letter if and only if x will cook. There is at least one x for which x will cook if and only if x will write a letter.