Dear students,

this email is mostly to check that you are all in my email list. If you have some friends enrolled in the course who did not receive this message, please ask them to notify it to me.

Also, I have a clarification about the problem set (I thank the students who pointed this out).
In Problem 3(1), the symbol
Z\{0}
is to denote the difference of sets, i.e. it is the same as
Z-{0}
namely the set of all integers except the number 0.

Sincerely,

Alberto

PS: if you received this message for the second time, it's perfect. If you received it for the first time, it's still ok. If you didn't receive it at all, please contact me.