Maps preserving the Douglas solution of operator equations

Zsigmond Tarcsay

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arXiv · 2102.13106

Maps preserving the Douglas solution of operator equations

Zsigmond Tarcsay

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Abstract

We consider bijective maps $\phi$ on the full operator algebra $\mathcal{B}(\mathcal{H})$ of an infinite dimensional Hilbert space with the property that, for every $A,B,X\in \mathcal{B}(\mathcal{H})$, $X$ is the Douglas solution of the equation $A=BX$ if and only if $Y=\phi(X)$ is the Douglas solution of the equation $\phi(A)=\phi(B)Y$. We prove that those maps are implemented by a unitary or anti-unitary map $U$, i.e., $\phi(A)=UAU^*$.

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Zsigmond Tarcsay. 2021-02-25. Maps preserving the Douglas solution of operator equations. https://arxiv.org/abs/2102.13106

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