What are the contribution of the mathematician Henri Poincare?

As a mathematician and physicist, he made many original fundamental contributions to pure and applied mathematics, mathematical physics, and celestial mechanics. He was responsible for formulating the Poincar� conjecture, one of the most famous problems in mathematics. In his research on the three-body problem, Poincar� became the first person to discover a chaotic deterministic system which laid the foundations of modern chaos theory. He is also considered to be one of the founders of the field of topology.