Abstract: | Abstract. This survey is organized as follows. I. Introduction. II. The main issues. III. Negishi's model. IV. Objective demand in the Cournot-Nash framework. V. Objective demand in the Bertrand-Nash framework. VI. The assumption of quasi-concavity of the profit functions. VII. Compromises between the conjectural and the objective approach. VIII. Insights into the notion of perfect competition. IX. Conclusion. |