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 fast. Sarah is playing squash if and only if Linda is fast. For all y, if y were fast, then y is driving a car. For all y, y will not drive a car.
If Sarah plays squash, then Linda is fast can be inferred via the biconditional elimination rule. If Linda were fast, then Sarah is playing squash can be inferred via the biconditional elimination rule. For all y, y is not fast can be inferred via the universal modus tollens rule. For all y, y will drive a car if and only if y is fast can be inferred via the universal biconditional introduction rule. For all y, y is fast if and only if y will drive a car can be inferred via the universal biconditional introduction rule.