Give an example of sigma algebra in $\mathcal P(\Bbb N)$ whose order is finite, and also whose order is infinite, and whose order is $10$?
(the order means the number of elements)
Give an example of sigma algebra in $\mathcal P(\Bbb N)$ whose order is finite, and also whose order is infinite, and whose order is $10$?
(the order means the number of elements)