“…Let us first recall (see [12]) that an ODL is an algebra L = (X, ∧, ∨, ⊥ , 0, 1, ), where : X 2 → X is a binary operation and (X, ∧, ∨, ⊥ , 0, 1) is an orthocomplemented lattice. The presence of the "symmetric difference" makes ODLs fairly close to Boolean algebras -for instance, (X, ∧, ∨, ⊥ , 0, 1) is an orthomodular lattice and (X, ) is a 2-group.…”