Marie Ennemond Camille Jordan (January 5, 1838 – January 22, 1922) was a French mathematician, known both for his foundational work in group theory and for his influential Cours d'analyse. He was born in Lyon and educated at the École polytechnique. He was an engineer by profession; later in life he taught at the École polytechnique and the Collège de France, where he had a reputation for eccentric choices of notation.
He is remembered now by name in a number of foundational results:
* The Jordan curve theorem, a topological result required in complex analysis
Jordan's work did much to bring Galois theory into the mainstream. He also investigated the Mathieu groups, the first examples of sporadic groups. His Traité des substitutions, on permutation groups, was published in 1870.
The asteroid 25593 Camillejordan and Institute of Camille Jordan are named in his honour.
Camille Jordan is not to be confused with the geodesist Wilhelm Jordan (Gauss-Jordan elimination) or the physicist Pascual Jordan (Jordan algebras).
Books by C. Jordan
* Cours d'analyse de l'Ecole Polytechnique ; 1 Calcul différentiel (Gauthier-Villars, 1909)
* Jordan-Chevalley decomposition
* O'Connor, John J.; Robertson, Edmund F., "Camille Jordan", MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Jordan.html .