<title>Abstract</title> On the basis of the 19th century mathematical economics literature initiated by Cournot, the paper shows the coexistence of two contrasting views of competition, which may be associated, as already suggested by Edgeworth, with the two themes of peace and war. According to the first view...

<title>Abstract</title> Cournot's <italic>Recherches</italic> contains a sketch of the general equilibrium research programme, as well as the model of an exchange economy as a system verifying Walras' law. General equilibrium analysis had nonetheless to wait for Walras to occupy the centre of theoretical economics, since it...

The paper suggests a <italic>new Keynesian</italic> model of the <italic>General Theory</italic>. A reduced form entails a diagram with three curves relating employment and the real wage, which represent the two fundamental classical postulates and the principle of effective demand. This diagram illustrates better than <italic>IS-LM</italic> the...