During his time at Kiel, Hasse kept in close contact with the mathematicians at Hamburg including Artin, Hecke, Ostrowski and Schreier .
Sa panahon ng kanyang oras at Kiel, Hasse iningatan sa malapit na makipag-ugnayan sa mathematicians sa Hamburg kasama ang Artin, Hecke, Ostrowski at Schreier.