Hilbert space
Posted: Tue Nov 07, 2017 11:12 am
Let \(\displaystyle{\left(H,\langle{,\rangle}\right)}\) be a Hilbert space. We set
\(\displaystyle{\ell^2(H):=\left\{x:\mathbb{N}\to H\,,\sum_{n=1}^{\infty}||x_{n}||^2<\infty\right\}}\).
and
\(\displaystyle{\langle{x,y\rangle}:=\sum_{n=1}^{\infty}\langle{x_n,y_n\rangle}\,,\forall\,x\,,y\in \ell^2(H)}\).
Prove that \(\displaystyle{\left(\ell^2(H),\langle{,\rangle}\right)}\) is a Hilbert space which contains
\(\displaystyle{H}\).
\(\displaystyle{\ell^2(H):=\left\{x:\mathbb{N}\to H\,,\sum_{n=1}^{\infty}||x_{n}||^2<\infty\right\}}\).
and
\(\displaystyle{\langle{x,y\rangle}:=\sum_{n=1}^{\infty}\langle{x_n,y_n\rangle}\,,\forall\,x\,,y\in \ell^2(H)}\).
Prove that \(\displaystyle{\left(\ell^2(H),\langle{,\rangle}\right)}\) is a Hilbert space which contains
\(\displaystyle{H}\).