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arXiv · 2502.01761

Matrix systems, algebras, and open maps

Stephan Weis
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Abstract

Every state on the algebra $M_n$ of complex nxn matrices restricts to a state on any matrix system. Whereas the restriction to a matrix system is generally not open, we prove that the restriction to every *-subalgebra of $M_n$ is open. This simplifies topology problems in matrix theory and quantum information theory.

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Stephan Weis. 2025-02-03. Matrix systems, algebras, and open maps. https://doi.org/10.1007/s43036-025-00448-8

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