I want to know the answer to the following question:
What was the topic of Von Neumann's work at Princeton in 1931 - 32?
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