Efficient and optimal programs when investment is irreversible: A duality theory

An attempt is made in this paper to formulate a satisfactory duality theory of efficient and optimal programs in intertemporal models with irreversible inveatment. The introduction of the constraint that depreciated capital stock cannot be used for present consumption makes the meaningful choice and interpretation of dual variables a more difficult problem, as is pointed out by means of an example. A new definition of a competitive program is introduced, and this is seen to lead to useful characterizations of efficient and optimal programs.