Stephen Smale
Stephen Smale (born July 15, 1930) is an American mathematician and winner of the Fields Medal in 1966. He made his reputation by a proof of the Poincare conjecture for all dimensions greater than 4. He then turned to the study of dynamical systems, where he made significant advances as well as outlining a research program carried out by many others. Smale is also known for work in mathematical economics, as well as recent explorations of various theories of computation.
In 1998 he constructed a list of 18 problems in mathematics to be solved in the 21st century. This list was compiled in the spirit of Hilbert's famous list of problems produced in 1900. In fact, Smale's list includes some of the original Hilbert problems. Smale's problems include the Jacobian conjecture and the Riemann hypothesis, both of which are still unsolved.
Stephen Smale is also famous for the proof of sphere eversion. That is, turning a sphere inside out without creating any crease.
