Ockham algebra
In mathematics, an Ockham algebra is a bounded distributive lattice L {\displaystyle L} with a dual endomorphism, that is, an operation ∼ : L → L {\displaystyle \sim \colon L\to L} satisfying ∼ ( x ∧ y ) = ∼ x ∨ ∼ y {\displaystyle \sim (x\wedge y)={}\sim x\vee {}\sim y} , ∼ ( x ∨ y ) = ∼ x ∧ ∼ y {\displaystyle \sim (x\vee y)={}\sim x\wedge {}\sim y} , ∼ 0 = 1 {\displaystyle \sim 0=1} , ∼ 1 = 0 {\displaystyle \sim 1=0} . They were introduced by Berman, and were named after William of Ockham by Urquhart.