Abstract
We study two inequalities which are concerned with \({\mathbf {T}}\)-martingales. More precisely, we establish the noncommutative Azuma inequality for \({\mathbf {T}}\)-martingales and noncommutative \({\mathbf {T}}\)-martingale deviation inequality using the Golden–Thompson inequality for a positive module operator. The inequalities in this paper are considered as generalizations of the inequalities for a conditional expectation and a state. As an application, we study some convergence results which are concerned with the weak law of large numbers for weighted sums in a noncommutative probability space.
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Acknowledgements
This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. 2020R1C1C1A01003305). The author thanks the anonymous referees for valuable comments on this paper.
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Communicated by M. S. Moslehian.
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Choi, B.J. Inequalities for martingales with respect to positive module operators. Adv. Oper. Theory 5, 1455–1467 (2020). https://doi.org/10.1007/s43036-020-00054-w
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DOI: https://doi.org/10.1007/s43036-020-00054-w
Keywords
- Module operator
- Conditional expectation
- Golden–Thompson inequality
- Noncommutative Azuma inequality
- Martingale deviation inequality