Leopold Löwenheim
Leopold Löwenheim (26 June 1878 in Krefeld – 5 May 1957 in Berlin) was a German mathematician doing work in mathematical logic. The Nazi regime forced him to retire because under the Nuremberg Laws he was considered only three quarters Aryan. In 1943 much of his work was destroyed during a bombing raid on Berlin. Nevertheless, he survived the Second World War, after which he resumed teaching mathematics. Löwenheim (1915) gave the first proof of what is now known as the Löwenheim–Skolem theorem, often considered the starting point for model theory. Leopold was the son of Ludwig Löwenheim , a mathematics teacher at the polytechnic in Krefeld and Elizabeth Röhn, a writer. In 1881 the three of them left Krefeld first for Naples and then Berlin where Ludwig was a private scholar working on a comprehensive account of the influence of Democritus on modern science. Although he hoped this would gain him a teaching job at Humboldt University Ludwig died in 1894.