Paul Frederick Zweifel

Paul Frederick Zweifel (June 21, 1929 – February 12, 2017) was a mathematical physicist and a prominent leader in the mathematical theory of nuclear reactors and the mathematical development of linear transport theory, a discipline that encompasses neutron transport in the core of a nuclear reactor as well as the propagation of photons in radiative transfer.

In transport theory, he pioneered the use of rigorous mathematics for analytically solving the linear transport equation. He developed existence and uniqueness theorems for the neutron transport equation and investigated the spectrum of the linear transport operator under general conditions. Provided by Wikipedia