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2 votes
1 answer
316 views

Decomposition of Hilbert spaces via groups and algebras representations

Let $\mathcal{H}$ be a complex finite dimensional Hilbert space and let $\mathcal{A}\subseteq \mathcal{B}(\mathcal{H})$. I am looking to understand the different decompositions of $\mathcal{H}$ ...
vand's user avatar
  • 23
1 vote
1 answer
247 views

Linearity of the directional derivative of a convex functional at the minimum

Let $H$ be a Hilbert space, $T_+(H)$ the set of positive self-adjoint trace-class operators on $H$, and $f : T_+(H) \to [0,m]$ a non-negative, bounded, convex functional. I don't necessarily know that ...
Artemy's user avatar
  • 695
3 votes
1 answer
325 views

Reference on completely positive maps which are isometries

Let $\Phi:\mathcal{L}(H)\rightarrow \mathcal{L}(K)$ be a completely positive map sending positive self-adoint operators on a finite-dimensional Hilbert space $H$ to positive self-adoint operators on a ...
Stefano Gogioso's user avatar
1 vote
2 answers
285 views

a follow up question on traces of matrices

In a recent MO post, pallab1234 ask for trace inequalities for which counterexample were given. I wish to probe in a different direction. Suppose $A, B$ are $n\times n$ symmetric matrices (with ...
T. Amdeberhan's user avatar
1 vote
0 answers
108 views

Reference request on operator matrices [closed]

I'm looking for a reference on linear, bounded, self-adjoint operators defined on the product space, $T:E\times F\to E\times F$ such that $$Tx = \begin{pmatrix}A & B \\ C & D \end{pmatrix}\...
Aad's user avatar
  • 11