Commutative residual algebras

the inclusion-exclusion principle


We present a version of the inclusion-exclusion principle (IE) that can be stated and proven for commutative residual algebras (CRAs). By lifting CRAs to lattice-ordered groups the usual formulation of the IE is recovered. This provides a uniform proof of IE that applies to natural numbers with both (cut-off) subtraction or division, and for the CRAs of (measurable) (multi)sets.