3. The system of claim 2 where the ZDD is formed by manipulatively combining an Elective Events ZDD component with the rule model to invoke a data processing event responsive to a predetermined combination of constraints of the rule model.
3. The system of claim 2 where the ZDD is formed by manipulatively combining an Elective Events ZDD component with the rule model to invoke a data processing event responsive to a predetermined combination of constraints of the rule model. 5. The system of claim 3 where the data processing event includes performing a calculation.