NY Times columnist and economist Paul Krugman Mar 17 2008
This paper extends interplanetary trade theory to an interstellar setting. It is chiefly concerned with the following question: how should interest charges on goods in transit be computed when the goods travel at close to the speed of light? This is a problem because the time taken in transit will appear less to an observer travelling with the good than to a stationary observer. A solution is derived from economic theory, and two useless but true theorems are proved.