in the first epoch (1907–1919), noether dealt primarily with differential and algebraic invariants, beginning with her dissertation under paul gordan. her mathematical horizons broadened, and her work became more general and abstract, as she became acquainted with the work of david hilbert, through close interactions with a successor to gordan, ernst sigismund fischer. after moving to göttingen in 1915, she produced her work for physics, the two noether's theorems.