What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x, x is a soldier if and only if x will climb a mountain. There is at least one x for which x will write a letter if and only if x will climb a mountain. For all x, x will not write a letter.
For all x, if x were a soldier, then x is climbing a mountain. There is at least one x for which if x writes a letter, then x is climbing a mountain. For all x, if x climbs a mountain, then x is a soldier. There is at least one x for which if x climbs a mountain, then x is writing a letter. There is at least one x for which x will not climb a mountain.