New posts in hilbert-spaces

Is the identity map $id: H^2(-\pi,\pi) \to L^2(-\pi,\pi)$ Hilbert-Schmidt?

Spanning set for $L^2(S^2)$?

$W_0^{1,p}(\Omega)\neq W^{1,p}(\Omega)$

Is compactness a stronger form of continuity?

Transforming a distance function to a kernel

Rademacher functions form an orthonormal system but not an orthonormal basis

Direct sum of orthogonal subspaces

Explicit characterization of dual of $H^1$

Confusion about the Hamel Basis

Every Hilbert space has an orthonomal basis - using Zorn's Lemma

Show linear independence of a set of vectors close to an orthonormal basis

Can we infer that $\text{Im}(P)=S$ if $\Vert P(x)-x\Vert =\min\big\{\Vert y-x\Vert :y\in S\big\}$ for all $x\in H$? [closed]

On existence of a bounded linear functional $f.$

Density of finite rank operator in compact operators on Hilbert spaces

Vector, Hilbert, Banach, Sobolev spaces

Properties of reflexive Banach spaces

Why isn't every element of the spectrum an eigenvalue? (Where is the error in my proof?)

An example of non-closed subspace of a Hilbert space?

Orthogonal projection on the Hilbert space .

A problem with inner products on Hilbert space