Globals are named objects that are made visible to the rule engine, but unlike facts, changes in the object backing a global do not trigger reevaluation of rules. Globals are useful for providing static information, as an object offering services that are used in the RHS of a rule, or as a means to return objects from the rule engine. When you use a global on the LHS of a rule, make sure it is immutable, or else your changes will not have any effect on the behavior of your rules.