Joseph Diaz Gergonne

Joseph Diaz Gergonne ( born June 19, 1771 in Nancy, † May 4, 1859 in Montpellier) was a French mathematician.

Gergonne was the son of a painter and architect. He attended school in Nancy. In 1792 he went as one of the many volunteers in the Revolutionary War and was among others the victory of the French revolutionary army in the cannonade of Valmy. After a short time in Paris in 1793 he was secretary of the General Staff of the French Army Mosel. After one month visit to the artillery school, he became a lieutenant in 1794 and went with the French army to Spain, where he was with the conquest of this Figueres. After the separate peace with the Prussians in 1795 he left the army, was in Nimes Professor of Mathematics and married. In 1810 he founded the Annales de Mathématiques et pure appliquées called Annales de Gergonne. It existed until 1832, and published, among other things Jean -Victor Poncelet, Michel Chasles, Jacob Steiner, Julius Plücker, Évariste Galois. In 1816 he was astronomy professor in Montpellier. In 1830 he was rector there in 1844 and went into retirement.

Gergonne itself was mainly concerned with geometry. He coined the word polar in projective geometry, and he led there, the principle of duality one ( from 1810, especially from 1824 to 1827 ). He noted that rates of projective geometry could be converted by replacing the terms point and line together. He was also in 1816 an elegant solution to the problem of Apollonius ( constructing a circle which touches three given circles). In the triangular geometry of the Gergonne - spot is named after him.