The quantity-setting (Cournot) oligopoly with perfect complements is dual to the price-setting (Bertrand) oligopoly with homogeneous goods. Under mild technical conditions, the former setting has a unique (pure strategy) Nash equilibrium with null quantities

One of the pioneering works on endogenous market structures, by Tandon (1984), has extended the standard Cournot model with linear demand to endogenous entry and sunk R&D costs to show that the endogenous number of firms is independent from the size of the market. I generalize the model in many...