Marie Ennemond Camille Jordan (5 January 1838 – 22 January 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.