I want to know the answer to the following question:
What work did Von Nemann do in Berlin in 1930 and Princeton 1935 - 39?
All the background I'm provided with is that "Also, my work on various forms of operator theory, Berlin 1930 and Princeton 1935–1939; on the ergodic theorem, Princeton, 1931–1932."". Is that enough to answer the question?
Answer: yes