Before revision: Then we can inquire what the validity of this cue is with regard to the following classes: {rational number, irrational number, even integer}: If we know that a number is a positive integer we know that it is rational number.
After revision: aThen we can inquire what the validity of this cue is with regard to the following classes: {rational number, irrational number, even integer}: If we know that a number is a positive integer we know that it is rational number.