Hernan Vallejo2026-03-222026-03-22202510.15446/ede.v35n67.118740https://doi.org/10.15446/ede.v35n67.118740https://andeanlibrary.org/handle/123456789/78949This article develops a simple linear model of oligopoly and uses it to provide a detailed characterization of equilibrium prices, quantities, mark-ups, price elasticities of market demand; and welfare, all in terms of the parameters of the model. This is done under five different conjectures: Collusion, Threat, Cournot, Stackelberg, and Bertrand. The results of the model are used for comparative statics.esOligopolyEconomicsSimple (philosophy)EconometricsMathematical economicsStability (learning theory)MicroeconomicsCharacterization (materials science)General equilibrium theoryarticle