Let \(Y\) be a subspace of a Hilbert space \(H\). Show that \(Y\) is closed if and only if \(Y=Y^{\perp \perp }\).
Question
Math 6420 • PDE
Spring 2016 • Question 4
Question
Spring 2016 • Question 4
Let \(Y\) be a subspace of a Hilbert space \(H\). Show that \(Y\) is closed if and only if \(Y=Y^{\perp \perp }\).