Abstract
Necessary and sufficient conditions are obtained for operator partial 2 × 2 matrices to have an idempotent completion, and all such completions are parametrically represented.
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Project supported by National Natural Science Foundation of China and Provincial Natural Science Foundation of Shanxi
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Hou, J., Radjavi, H. & Rosenthal, P. Idempotent completions of operator partial matrices. Acta Mathematica Sinica 15, 333–346 (1999). https://doi.org/10.1007/BF02650728
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DOI: https://doi.org/10.1007/BF02650728