Classical theories of exchange rates, such as Mint Par and Purchasing Power Parity (PPP), have the desirable property that they define a network of exchange rates in which no profit by 'compound arbitration' or 'cyclic arbitrage' is possible. Conversely, it will be shown that any network of...

A new and powerful dictatorship result is presented. It is well known that in social choice problems, the negativism of the original Arrow result can be overcome by admitting information based on interpersonal comparisons. But what if individuals in society have different opinions about htese...