New posts in operator-theory

Example of a self-adjoint bounded operator on a Hilbert space with empty point spectrum

Positive operator on a complex Hilbert space is symmetric?

Spectral measure of the multiplication operator

Fourier transform as a Gelfand transform

Spectral Measures: Square Root

Strong convergence of operators

How to prove Halmos’s Inequality

What is a Form Domain of an Operator?

If the image of an orthonormal basis is bounded, is the linear operator also bounded?

fact used in C*-algebra proofs.

finite dimensional range implies compact operator

Continuity of the adjoint map in various operator topologies

Is the multiplier algebra $M(K(H)\otimes C(X))$ isomorphic to $M(K(H))\otimes C(X)$?

$C^*$-homomorphisms and compact $T_2$ spaces

Prove that $A$ is bounded operator on $\ell^p$ and find $\| A\|$

Infinite-dimensional inner product space: if $A \geq 0$ and if $\langle Ax, x\rangle = 0$ for some $x$, then $Ax = 0$.

Nonnegativity of integral, integral operator

CFT's vs Vertex Operator Algebras

$5$ questions on the definition of the Gelfand triple

Norms of linear maps