Don Zagier

Don Zagier

Don Bernard Zagier (born 29 June 1951) is an American mathematician whose main area of work is number theory. He is currently one of the directors of the Max Planck Institute for Mathematics in Bonn, Germany, and a professor at the Collège de France in Paris, France.

He was born in Heidelberg, Germany. His mother was a psychiatrist, and his father was the dean of instruction at the American College of Switzerland. His father held five different citizenships, and he spent his youth living in many different countries. After finishing high school (at age 13) and attending Winchester College for a year, he studied for three years at M.I.T., completing his bachelor's and master's degrees and being named a Putnam Fellow in 1967 at the age of 16. He then wrote a doctoral dissertation on characteristic classes under Friedrich Hirzebruch at Bonn, receiving his PhD at 20. He received his Habilitation at the age of 23, and was named professor at age 24.

He has collaborated with Hirzebruch in work on Hilbert modular surfaces. One of his most famous results is a joint work with Benedict Gross (the so-called Gross–Zagier formula). This formula relates the first derivative of the complex L-series of an elliptic curve evaluated at 1 to the height of a certain Heegner point. This theorem has many applications including implying cases of the Birch and Swinnerton-Dyer conjecture along with being a key ingredient to Dorian Goldfeld's solution of the class number problem.

He also is known for discovering a short and elementary proof of Fermat's theorem on sums of two squares.

Zagier won the Cole Prize in Number Theory in 1987 and the von Staudt Prize in 2001.