The French Mathematician Antoine Augustin Cournot Founded Modern Monopoly and Perfect-Competition Theories

Meanwhile, unheralded and unrecognized at the time, the French mathematician Augustin Cournot, founded not only mathematical economics but also modern monopoly and perfect-competition theories, in his Principes in 1838. To make things easy for using the calculus in dealing with profits, revenues, and costs of a business firm, Cournot defined competition as that situation where price does not vary with the quantity of the good produced: i.e., where the demand curve for the firm is horizontal, or “perfectly elastic.” Not only did Cournot thus found the basic axiom of perfect competition theory, he also believed that such a condition only obtains where the number of firms is large, and that when firms are fewer, “oligopoly” ensues. Cournot worked out a theory of “duopoly.”

Thus, with Cournot, the seeds of modern perfect-competition and monopolistic-competition theories were already set, as well as modern mathematical economics: “competition” only occurs when the demand curve for the firm is horizontal; this takes place only when the number of firms in the industry is very large; a smaller number leads to “monopolistic” situations of “oligopoly,” etc. Of course, a single firm in an industry, where the demand curve is of course falling, Cournot defined as a “monopoly.”

—Murray N. Rothbard, “Competition and the Economists,” Quarterly Journal of Austrian Economics 15, no. 4 (Winter 2012): 400-401.