The Parallel Sum for Adjointable Operators on Hilbert C*-Modules

Wei LUO, Chuan Ning SONG, Qing Xiang XU

Acta Mathematica Sinica, Chinese Series ›› 2019, Vol. 62 ›› Issue (4) : 541-552.

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Acta Mathematica Sinica, Chinese Series ›› 2019, Vol. 62 ›› Issue (4) : 541-552. DOI: 10.12386/A2019sxxb0051

The Parallel Sum for Adjointable Operators on Hilbert C*-Modules

  • Wei LUO, Chuan Ning SONG, Qing Xiang XU
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Abstract

The parallel sum for adjointable operators on Hilbert C*-modules is introduced and studied. Some results known for matrices and bounded linear operators on Hilbert spaces are generalized to the case of adjointable operators on Hilbert C*-modules. It is shown that there exist a Hilbert C*-module H and two positive operators A, BL (H) such that the operator equation A1/2=(A + B)1/2X, XL (H) has no solution, where L (H) denotes the set of all adjointable operators on H.

Key words

Hilbert C*-module / Moore-Penrose inverse / parallel sum

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Wei LUO, Chuan Ning SONG, Qing Xiang XU. The Parallel Sum for Adjointable Operators on Hilbert C*-Modules. Acta Mathematica Sinica, Chinese Series, 2019, 62(4): 541-552 https://doi.org/10.12386/A2019sxxb0051

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