John Alden Thorpe (February 29, 1936 – January 18, 2021) was an American mathematician, known for contributions to the field of differential geometry.
[1] Thorpe obtained his Bachelor's degree in 1958 from the Massachusetts Institute of Technology.
His Ph.D. was done at Columbia University, under the direction of James Eells (Higher Order Sectional Curvature).
[2] From 1963 to 1965, he was Moore Instructor at MIT and Assistant Professor at Haverford College in 1965.
He and Nigel Hitchin independently found an inequality between topological invariants, which provides a necessary condition for the existence of Einstein metrics on four-dimensional smooth compact manifolds.