The composition of such two constraints is the constraint  that is satisfied by every evaluation of the two non-shared variables for which there exists a value of the shared variable  such that the evaluation of these three variables satisfies the two original constraints  and .
The combination of such two constraints is the constraint that is satisfied by every evaluation of the two non-overlapping variables for which there exists a value of the shared variable such that the evaluation of these three variables satisfies the two original constraints and , implying an intersection or overlap between the constraints.