Hale Trotter
Hale Freeman Trotter (30 May 1931 – 17 January 2022) was a Canadian-American mathematician, known for the Lie–Trotter product formula, the Steinhaus–Johnson–Trotter algorithm, and the Lang–Trotter conjecture. He was born in Kingston, Ontario. He died in Princeton, New Jersey on January 17, 2022. Trotter studied at Queen's University in Kingston with bachelor's degree in 1952 and master's degree in 1953. He received in 1956 his PhD from Princeton University under William Feller with thesis "Convergence of semigroups of operators". Trotter was from 1956 to 1958 at Princeton University the "Fine Instructor