For 10 points, name this French mathematician who names a conjecture proven by Grigori Perelman which states that every closed, simply connected manifold is homeomorphic to the three-sphere.
John Stallings's "engulfing" method was used to solve one problem named for this man using the notion of PL-homotopy. A problem named for this mathematician was introduced in the same paper that showed that a certain object had a fundamental group of over 120. Michael Freedman solved a special case of a generalized version of that problem named for this man, which was solved for dimension higher than four by Stephen Smale. Richard Hamilton outlined a method of using Ricci flows to solve that problem named for this man. For 10 points, name this French mathematician who names a conjecture proven by Grigori Perelman which states that every closed, simply connected manifold is homeomorphic to the three-sphere.
John Stallings's "engulfing" method was used to solve one problem named for this man using the notion of PL-homotopy.
Henri Poincaré