Furthermore, the cumulative probability S(5) associated with the second symbol a5 must be calculated. Thus, the sub-interval corresponding to the second symbol a5 is a second sub-interval within the first sub-interval corresponding to a0. Mathematically, the width A2 of the second sub-interval is equal to p(0)*p(5), i.e. the product of the probabilities of occurrence of both symbols a0 and a5. The starting point of the second sub-interval within the unit interval depends on the width A1 of the first sub-interval and the cumulative probability S(5) associated with the second symbol a5, being equal to their product A1*S(5).