Joseph Louis François Bertrand, 1822-1900, was a French mathematician and economist who was Professor at the École Polytechnique and a member of the Collège de France.
With regards to economics, Bertrand is mostly known for reviewing the articles “Théorie mathématique de la richesse sociale” and “Recherches sur les principes mathématiques de la théorie des richesses” by Leon Walras and Antoine Cournot respectively, which were published at the Journal des Savants in 1883. He criticized Walras’ process of tâttonnement, as he argued that in real life there are transactions that take place under non-balanced situations and so we can consider a non-determination in pricing. The critique to Cournot had greater value for economics, as it further developed both game theory and oligopoly theory, creating another model for duopolies, known as the Bertrand duopoly model. The main difference between Cournot’s view on duopolies and Bertrand’s is that the latter assured that duopolies competition would be linked to prices and not to their production quantity, as was proposed by Cournot.