We analyze how sharing rules affect Nash equilibria in Bertrand games, where the sharing of profits at ties is a decisive assumption. Necessary conditions for either positive or zero equilibrium profits are derived. Zero profit equilibria are shown to exist under weak conditions if the sharing...

We prove the existence of symmetric pure Cournot equilibria with heterogeneous goods under the following condition: each firm reacts to a rise in competirors output in such a way that its market price does not rise. This condition is not related to wether goods are strategic substitutes or...

We analyze the impact of mandatory access on the infrastructure investments of two competing communications networks, and show that for low (high) access charges ?rms wait (preempt each other). Contrary to previous results, under preemption a higher access charge can delay ?rst investment. While...

The European Union will be introducing a Europe-wide patent, the so-called Community Patent. Its aim is to foster innovative activity, but strategic effects between firms competing in R&D have not been considered in the official discourse. We show that, even if these are taken into account, the...