Western Europe was plagued with currency shortages from the 14th to the 19th century, at which time a `standard formula' had been devised to cure the problem. We document the evolution of mon- etary theory, policy experiments and minting tech- nology over the course of six hundred years. In a...

This paper constructs a model with two structural equations: the Government budget constraint and a linear version of Cagan’s portfolio balance equation. The model contains a continuum of equilibria with “sunspot equilibria.” Closed forms for the solutions are found. Even though there is a...

For each of three types of ambiguity, we compute a robust Ramsey plan and an associated worst-case probability model. Ex post, ambiguity of type I implies endogenously distorted homogeneous beliefs, while ambiguities of types II and III imply distorted heterogeneous beliefs. Martingales...

This paper studies alternative ways of representing uncertainty about a law of motion in a version of a classic macroeconomic targetting problem of Milton Friedman (1953). We study both “unstructured uncertainty” – ignorance of the conditional distribution of the target next period as a...

Lucas and Stokey (1983) motivated future governments to confirm an optimal tax plan by rescheduling government debt appropriately. Debortoli et al. (2021) showed that sometimes that does not work. We show how a Ramsey plan can always be implemented by adding instantaneous debt to Lucas and...