Michel Lazard

Michel Paul Lazard (5 December 1924 – 15 September 1987) was a French mathematician who worked in the theory of Lie groups in the context of p-adic analysis. His work took on a life of its own in the hands of Daniel Quillen in the late 20th century. Quillen's discovery, that a ring Lazard used to classify formal group laws was isomorphic to an important ring in topology, led to the subject of chromatic homotopy theory.

Lazard's self-contained treatise on one-dimensional formal groups also gave rise to the field of p-divisible groups.

His major contributions are:

• The classification of p-adic Lie groups: every p-adic Lie group is a closed subgroup of ${\displaystyle {\rm {GL}}_{n}(\mathbb {Z} _{p})}$.
• The classification of (1-dimensional commutative) formal groups.
• The universal formal group law coefficient ring (Lazard's universal ring) is a polynomial ring.
• The concept of "analyseurs", reinvented by J. Peter May under the name operads.