Kurt Heegner ( ; 16 December 1893, Berlin – 2 February 1965, Berlin) was a German private scholar from Berlin, who specialized in radio engineering and mathematics. He is now famous for his mathematical discoveries in number theory.
In 1952 Heegner published what he claimed was the solution of a classic problem proposed by the great mathematician Gauss, the class number 1 problem, a significant and longstanding problem in number theory. Heegner's work was not accepted for years, due mainly to mistakes in the paper. Heegner's proof was finally accepted as essentially correct in 1969, after Harold Stark, who had independently arrived at a similar proof, showed that Heegner's proof was more or less equivalent to his own, with only a minor gap in it. Stark attributed Heegner's mistakes to the fact he was using a textbook by Weber which contained some results with incomplete proof. However this was four years after Heegner's death, and he never saw his proof become widely accepted.