Louis Bertrand (mathematician)

Louis Bertrand (3 October 1731 – 15 May 1812) was a Swiss mathematician.

Biography
He was born, lived and died in Geneva, where he published the work Developpement nouveau de la partie elementaire des mathematiques (1778), which included a demonstration of Euclid's postulates that gained fame before the rise of non-Euclidean geometry and influenced most of the elementary geometry treatises of the 19th century.

He was a professor of mathematics at the University of Geneva from 1761 to 1795, becoming its rector in 1783. In 1774, he published the work De l'instruction publique in open opposition to Horace de Saussure's Projet de réforme pour le Collège de Genève.

He worked, besides in Geneva, also in Berlin, Bern, and London.