all platforms or a “pure” monopoly with just one platform. Literature has not generally discussed, which benchmark is the …

We propose both a monopoly and a duopoly model of a two-sided market. Both settings are fully comparable, as we impose … sizes. We determine the duopoly equilibrium and the monopoly optimum in terms of the parameters and obtain solutions with … economically plausible parameter sets for which duopoly equilibrium prices exceed optimal monopoly prices and one with no …

welfare and also aggregate consumer surplus even if, as in the benchmark linear case, total output does not increase …. Accordingly, the welfare criterion based on total output fails and should be replaced by the computation of well-defined price …