You can reach me via zexiangchen1227@gmail.com if,

1. You have any problems/concerns or find any typo in these materials. 
(I would be suprised if there aren't any).

2. You would like to add more material to the notes. I am happy to forward my LaTex, or add interesting topic you suggest.
(I am particularly interested in the topics I haven't done too much when I was in Cambridge)

3. You would like to improve the notes or the solutions to the exerciese.

4. NONE of above, but you simply love Maths :)