Bilinear forms (Existence of linear operator)
109512
Let f,g be bilinear forms on a finite dimensional vector space. Show that there exist unique linear operators
134981
Eigenvalues of $L^\dagger L$ are positive
82464
$U^*\otimes V$ versus $L(U,V)$ for infinite dimensional spaces
119352
compact and self adjoint square root of an operator
74147
Compactness of  Multiplication Operator on $L^2$
24177
Is there a comprehensive list of functions with operator forms?
144104
Show that a positive operator on a complex Hilbert space is self-adjoint
107992
Bilinear form with symmetric "perpendicular" relation is either symmetric or skew-symmetric
155509
Does a linear operator obeying Leibniz rule imply it is a differential operator?
45071
Having the derivative be an operator
137209
Finding the Matrix of a Linear Operator Satisfying a Polynomial
87676
Why is determinant a multilinear function?
151400
Closed-form of $\int_0^1 \operatorname{Li}_p(x) \, dx$
116558
Consider two linear operators $\hat{A}$ and $\hat{B}$. Show that $e^{\hat{A}}e^{\hat{B}}=e^{\hat{A}+\hat{B}}e^{[\hat{A},\hat{B}]/2}$
16692
a representation condition of Hilbert space
133609
orthonormal system in a Hilbert space
128457
Show that $T$ is a compact operator