Because properties and declarations are rules, the dependency network for a requestor depends on that requestor's RuleSet list.The dependency network is an internal data structure that supports forward chaining or automatic recalculation of certain property values based on changes to other property values.
You can establish required relationships among properties using a Declare Expression, Constraints, or Declare Index rule. Such rules are sometimes known as declarations. When an activity step changes the value or a property that is involved in a declaration, the system automatically consults the dependency network to see if other values are affected.
Because properties and declarations are rules, the dependency network for a requestor depends on that requestor's RuleSet list.
Operation of the dependency network is invisible and automatic; this can make dependencies difficult to test and debug.
Using Declare Expression rules, you can review the structure of dependencies defined. An example of this display appears at the right, for the property OrderTotal. You can access this display from:
Single Value properties. 
). The PegaSample sample application includes two properties that demonstrate Declare Expression rules, pyWorkListDateTime1 and Deadline. Three other standard Declare Expression rules apply to the Work- base class.
Related terms