Reduces the membership grade of the specified fact by the specified amount, removing it from the fact set if necessary, and reevaluates the rules in the system’s agenda.
- iOS 9.0+
- macOS 10.11+
- Mac Catalyst 13.0+
- tvOS 9.0+
An object representing a truth to be claimed or rejected by the rule system. For details, see the
The amount by which to reduce the fact’s membership grade.
Each fact has a membership grade ranging from zero to 1.0, representing variable levels of truth, strength, or confidence for use in fuzzy logic. Calling this method reduces the fact’s grade by the amount specified in the
grade parameter; reducing a fact’s grade to zero or below removes it from the
Upon asserting or retracting any facts, the system reevaluates the rules in its
agenda list so any rules that depend on changes to the set of facts can perform their actions.