Ernst Kummer (1810-1893). Caricature of the German mathematician Ernst Eduard Kummer. Kummer trained German army officers in ballistics. Afterwards, he taught for 10 years in a gymnasium, the German equivalent of high school, where he inspired the mathematical career of Leopold Kronecker. Kummer made several contributions to mathematics including codifying some of the relations between different hypergeometric series, known as contiguity relations. He also proved Fermat's last theorem for a considerable class of prime exponents.