It looks correct.
Of course, if A=B or or... there will be redundance.
Anyway, if you want to be 'clearer', you can change the complements (using de Moivre's formula)
the problem is the following: Let . Find the smallest -algebra ( ) on containing the sets and .
I have tried to answer this, and would appreciate if you could tell me if this the correct answer, or if I have left something out: