 Adjunctions can be composed in a natural fashion.Specifically, if 〈"F", "G", ε, η〉 is an adjunction between "C" and "D" and 〈"F"′, "G"′, ε′, η′〉 is an adjunction between "D" and "E" then the functor
is left adjoint to
More precisely, there is an adjunction between "F F"' and "G' G" with unit and counit given respectively by the compositions