One of the outstanding results of three decades of laboratory market research is that under rather weak conditions prices and quantities in competitive experimental markets converge to the competitive equilibrium. Yet, the design of these experiments ruled out gift exchange or reciprocity...

In a two-stage extensive form game where followers can observe moves by leaders only with noise, pure subgame perfect Nash equilibria of the limiting game without noise may not survive arbitrarily small noise. Still, for generic games, there is always at least one subgame perfect equilibrium...