Hello, thanks for reading.

Let (X,T) be a topologic space.

I got the next definition of "the closure of A, partial to X":

cl(A) = intersection (F | A is partial to F, F is closed in (X,T) )

I need to prove that cl(A) = AUA', where A' is the set of all accumulation points of A.

And aI don't succeed :-\

Thanks!

Tomer