# Problem Sheet C

This Problem Sheet is based on Lectures 5 and 6.

- Problem 1 gives a bunch more equivalent ways of formulating the weakly mixing property using two or three sets
^{[1]}. (Compare to Proposition 5.13.) - Problem 2 is (yet) another cute characterisation of weakly mixing systems.
- Problem 3 introduces the notion of
*totally transitive*systems, and asks you to prove that weakly mixing $ \Rightarrow$ totally transitive, and that totally transitive + chaotic $ \Rightarrow $ weakly mixing. - Problem 4 is fun (and harder than it looks).

This also shows that after I messed up the proof of Proposition 5.13 in lecture and drew the picture backwards my claim that "it didn't ↩︎

Comments and questions?