Louis Nirenberg

Louis Nirenberg (28 February 1925 – 26 January 2020) was a Canadian American mathematician. He was thought to be one of the outstanding analysts of the twentieth century. He made fundamental contributions to linear and nonlinear partial differential equations (PDEs) and their application to complex analysis and geometry. In 2015, he won the Abel Prize.
Nirenberg died at a Manhattan hospital on 26 January 2020 at the age of 94.