A partial characterization of the core in Bertrand oligopoly TU-games with transferable technologies

In this article we study Bertrand oligopoly TU-games with transferable technologies under the α and β-approaches (Aumann 1959). Although the convexity property does not always hold, we show that it is satisfied when firms' marginal costs are not too heterogeneous. Furthermore, we prove that the core of any game can be partially characterized by associating a Bertrand oligopoly TU-game derived from the most efficient technology. Such a game turns to be an efficient convex cover (Rulnick and Shapley 1997) of the original one. This result implies that the core is non-empty and contains a subset of payoff vectors with a symmetric geometric structure easy to compute