We study a model in which two carriers choose networks to connect cities and compete for travelling customers. We show that if carriers compete aggressively (e.g., Bertrand-like behavior), one carrier operating a single hub-spoke network is an equilibrium outcome. Competing hub-spoke networks...

In 1922 R. A. Fisher introduced the fixed X regression model, synthesising the regression theory of Pearson and Yule with the least squares theory of Gauss. The innovation was based on Fisher's realisation that the distribution associated with the regression coefficient was unaffected by the...

We consider environmental policy in a federal system where states face purely domestic environmental problems. It is normally argued that in this context, environmental policy is best set at the state level, perhaps because of better local information. To provide a rationale for federal...

In order to examine the optimum currency area case for EMU, we estimate structural VARs in output, the real exchange rate and prices for 14 EU countries and a small control sample. Using quarterly data since the end of bretton Woods, we find that (1) the data are strongly correlated for the...