**Claude Bouquet** was a French mathematician who worked on differential geometry and on series expansions of functions and elliptic functions.

- Jean-Claude became a school friend of Briot, who was also brought up in the Doubs region, and he went on to work with him for much of his life, collaborating both in teaching and in research.
- Bouquet was two years younger than Briot but they became friends at the Lycée since both had a fascination for mathematics.
- Bouquet was brought up in a period of unrest with the revolution of 1830.
- Bouquet entered the École Normale Supérieure in 1839, obtaining his doctorate in 1842 for a thesis Sur la variation des intégrales doubles Ⓣ(On the variation of double integrals) which he submitted to the Faculty of Science in Paris.
- Briot had been a school teacher of mathematics for a year before entering the École Normale Supérieure and he took one year longer to obtain his doctorate than Bouquet so the two friends obtained their doctorates in the same year.
- Bouquet was appointed professor of mathematics at the Lycée in Marseilles, then he went to Lyon as professor of mathematics in the Faculty of Science.
- Bouquet returned to Paris shortly before Louis-Napoleon declared himself emperor of the French on 2 December 1852; the Second Empire lasted until 1870.
- From 1852 until 1858 Bouquet taught at the Lycée Bonaparte (later renamed the Lycée Condorcet) in Paris.
- In 1858 Bouquet moved to the Lycée Louis-le-Grand, the school Galois had graduated from 30 years before, and there again put his energies into preparing pupils for the entrance examinations for the two major Paris universities.
- In 1874 Bouquet was appointed professor of differential and integral calculus at the Sorbonne, succeeding Serret who had retired due to ill health.
- Bouquet taught there until 1884, the year before his death.
- Bouquet worked on differential geometry, writing on orthogonal surfaces Note sur les surfaces orthogonales Ⓣ(Note on orthogonal surfaces) (1946).
- Bouquet and Briot developed Cauchy's work on the existence of integrals of a differential equation.
- Between 1859 and 1875 Bouquet worked with Briot on elliptic functions and Bouquet published an excellent text Théorie des fonctions elliptiques Ⓣ(Theory of elliptic functions) in 1875.
- Bouquet was as enthusiastic a teacher as he was researcher.
- It is worth commenting that although today joint research papers are the norm, this was certainly not the case in the time in which Bouquet worked.

Born 7 September 1819, Morteau, Doubs, France. Died 9 September 1885, Paris, France.

View full biography at MacTutor

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive