CHAPTER 01 · PERSON AND PERIOD
What questions surrounded Camille Jordan?
Before the finished achievement, read what this person treated as a problem and where the surviving evidence reaches its limit.
A mathematician who moved between pictures that look obvious and algebraic forms made computable. Jordan’s name remains attached to the curve theorem, canonical form, measure, and Jordan–Hölder theorem. His 1870 Treatise on Substitutions and Algebraic Equations organized the theory of permutation groups and equations developed after Galois and greatly helped group theory circulate. Calling it the solitary first textbook made directly from Galois’s scattered notes would erase the intervening research network. The attribution and formulation of Jordan form also involve earlier and later work. In 1887 he stated that a simple closed plane curve separates an inside from an outside, but the rigor of his argument was disputed; Veblen supplied a new proof in 1905. The story shows why an obvious-looking claim may still demand difficult definitions and proof.
