Let $(F_n )_{n \geq 1}$ be a sequence of algebras of subsets of a set $X$ . Under what conditions on $F_n$ can you conclude that $F:=\bigcup_{n=1}^{\infty}F_n$ is also an algebra ??
Bài viết đã được chỉnh sửa nội dung bởi thuylinh_909: 01-10-2015 - 09:51