Simon Norton, who has died of a heart attack aged 66, was a world-class mathematician sometimes mistaken for a homeless man. In the late 1960s he represented Britain at the International Mathematical Olympiads three times, scoring the top grade each time, once with 100%, another time with 99%, and winning a special prize for the elegance of his solutions. What made his work beautiful was not its complexity but its simplicity. Without drafts or false starts, he laid down his…