What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: For all y, if y drives a car, then y is sleeping. For all y, if y sleeps, then y is driving a car.
For all y, y will drive a car if and only if y will sleep can be inferred via the universal biconditional introduction rule. For all y, y will sleep if and only if y will drive a car can be inferred via the universal biconditional introduction rule.