Requirements in this document are designated as [RQx.yz], where x denotes the chapter number, y is a counter and z is an optional character to link closely related requirements. The following are examples of valid requirements designations: [RQ8.15] (requirement 15 in chapter 8); [RQ47.11a], [RQ47.11b] (requirements 11a and 11b in chapter 47, which are closely related).
The initial numbering of requirements was chosen such that counters within each chapter are in ascending order. However, the addition of further requirements leads to deviations from this rule since existing requirements shall keep their initial designation.
For an informative index of all the requirements in this document, see 10.4.