His doctoral work there was supervised by Frobenius, and Landau received his doctorate in 1899 for a thesis on number theory . Landau was always interested in mathematical puzzles and even before he received his doctorate he had published two books on mathematical problems in chess.
Ng doktor Kanyang trabaho doon ay supervised by Frobenius, at Landau natanggap ang kanyang titulo ng doktor sa 1899 para sa isang sanaysay sa numero ng teorya. Landau ay palaging interesado sa matematika puzzle at kahit bago niya natapos ang kanyang titulo ng doktor niya nai-publish ng dalawang mga libro sa matematika problema sa chess.