Delay equivalence in capital accumulation models

We study delays in capital accumulation models. Our contribution is threefold. First, we identify a class of models that can be transformed into standard optimal control models without delay. Second, in the single state versions of these models the state trajectory is monotonic in the optimal solution. This is noteworthy given the common belief that adding delays facilitates oscillatory behavior of capital, output and investment. Third, we identify an equivalence result between time-to-install/deliver problems and time-to-build problems.