Prove that any closed subspace of the space = $^{ℵ0}$, where is a discrete space of any power, is a retract of the space .
I think we can try to reduce the problem to this: Show that a retract of a Hausdorff space is closed..
But how can we neatly write that we can consider B as Hausdorff and solve the inverse problem: if there it follows from the fact that A is retracted that A is closed, then here it follows from the fact that A is closed that A is retracted.