What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If it snows, then David is not playing tennis. David is a carpenter or Mary is a politician. For all y, y is a carpenter if and only if y will play tennis. If Mary were a politician, then David is playing tennis.
For all y, if y were a carpenter, then y is playing tennis. For all y, if y plays tennis, then y is a carpenter.