Henri Poincare

Henri Poincare was a French mathematician, physicist and philosopher of science whose wide-ranging work made him one of the most influential figures across mathematics in the late nineteenth and early twentieth centuries. He is regarded as a founder of the field of topology, then called analysis situs, which studies properties of shapes that remain unchanged under continuous deformation, and he formulated the Poincare conjecture concerning the topological characterization of the three-dimensional sphere, a problem that remained open for nearly a century afterward. Poincare's study of the three-body problem in celestial mechanics led him to recognize that even simple deterministic systems could exhibit behavior too sensitive to initial conditions to predict over the long term, work now recognized as an early foundation of chaos theory. He also wrote extensively and influentially for a general audience on the philosophy of science and the nature of scientific discovery, and his work on the mathematics of relativity in the early 1900s closely paralleled, and partly anticipated, aspects of Einstein's special theory of relativity.