The famed Poincaré Conjecture - the only Millennium Problem cracked thus far.
More links & stuff in full description below ↓↓↓
Ricci Flow (used to solve the problem): http://youtu.be/hwOCqA9Xw6A
Riemann Hypothesis: http://youtu.be/d6c6uIyieoo
Extra interview footage with Jim Isenberg: http://youtu.be/7eJleW0JcKg
Grigori Perelman's paper: http://bit.ly/perelmanpaper
Discussed here by Katie Steckles and James Isenberg.
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