Effect algebra

Effect algebras are algebraic structures of a kind introduced by D. Foulis and M. Bennett to serve as a framework for unsharp measurements in quantum mechanics. Effect algebras are algebraic structures of a kind introduced by D. Foulis and M. Bennett to serve as a framework for unsharp measurements in quantum mechanics. An effect algebra consists of an underlying set A equipped with a partial binary operation ⊞, a unary operation (−)⊥, and two special elements 0, 1 such that the following relationships hold: Every effect algebra carries a natural order: define a ≤ b if and only if there exists an element c such that a ⊞ c exists and is equal to b. The defining axioms of effect algebras guarantee that ≤ is a partial order.