Grigori Perelman, the mathematician who declined both the Fields Medal and the $1,000,000 Clay Prize.

Grigori Perelman, the mathematician who declined both the Fields Medal and the $1,000,000 Clay Prize.

Grigori Perelman, a Russian mathematician, famously solved the Poincaré Conjecture, one of the seven Millennium Prize Problems, a challenge unsolved for nearly a century. His work in Ricci flow and geometry on 3-manifolds was groundbreaking, and his solution had a profound impact on the field. Despite worldwide recognition, Perelman declined the prestigious Fields Medal in 2006 and the $1 million Clay Prize in 2010, citing his dissatisfaction with the mathematical community and the handling of credit for collaborative efforts.

The Millennium Prize Problems are seven well-known complex mathematical problems selected by the Clay Mathematics Institute in 2000. The Clay Institute has pledged a US $1 million prize for the first correct solution to each problem.

The Clay Mathematics Institute officially designated the title Millennium Problem for the seven unsolved mathematical problems, the Birch and Swinnerton-Dyer conjecture, Hodge conjecture, Navier–Stokes existence and smoothness, P versus NP problem, Riemann hypothesis, Yang–Mills existence and mass gap, and the  Poincaré conjecture at the Millennium Meeting held on May 24, 2000.

Thus, on the official website of the Clay Mathematics Institute, these seven problems are officially called the Millennium Problems.

To date, the only Millennium Prize problem to have been solved is the Poincaré conjecture. The Clay Institute awarded the monetary prize to Russian mathematician Grigori Perelman in 2010. However, he declined the award as it was not also offered to Richard S. Hamilton, upon whose work Perelman built.