Nobel prize winning physicist Abdus Salam (https://en.wikipedia.org/wiki/Abdus_Salam https://en.wikipedia.org/wiki/Abdus_Salam) > During his doctoral studies,

Nobel prize winning physicist Abdus Salam (https://en.wikipedia.org/wiki/Abdus_Salam https://en.wikipedia.org/wiki/Abdus_Salam) > During his doctoral studies, his mentors challenged him to solve within one year an intractable problem which had defied such great minds as Dirac and Feynman.[29] Within six months, Salam had found a solution for the renormalisation of meson theory.