Constraintswhether

Constraintswhether is a coined term in constraint programming and related fields describing the conditional enforcement of a constraint under a boolean guard. The name combines the idea of a constraint with the interrogative “whether,” signaling that the constraint applies only when a condition holds.

Definition and semantics: Given a constraint C and a boolean guard g, the associated guarded constraint is represented as g implies C. In many solver models this is implemented as a reified constraint, where a boolean variable encodes the truth of C and controls its activation.

Examples: In scheduling with optional overtime, a constraint that total overtime does not exceed a limit is enforced only if overtime is chosen. In software product lines, feature-related restrictions apply only when the feature is included.

Relation to other concepts: Constraintswhether is related to guarded commands, reified constraints, and implication-based constraint modeling. It offers a concise way to express conditional constraints without duplicating problem structure for each feature combination.

Limitations and usage: Guards can increase propagation complexity and reveal subtle semantics if guards change during solving. Careful modeling is required to ensure that guard conditions correctly capture intended configurability. The concept is most useful in configurable, feature-rich, or interactive decision problems.