 Given a family

formula_4

of hom-set bijections, we call formula_5 an "adjunction" or an "adjunction between formula_6 and formula_7".If formula_8 is an arrow in formula_9, formula_10 is the right "adjunct" of formula_8 (p. 81).The functor formula_6 is left "adjoint" to formula_13, and formula_13 is right adjoint to formula_15.