Abstract
The classical Freedman inequality, as a martingale extension of the Bernstein inequality, gives an upper bound for the tail probabilities of a supermartingale whose difference sequence is bounded above. In this paper, by employing a result of Lieb–Araki concerning the concavity of a certain map and construction of special projections corresponding to the event of the tail probabilities, we establish some Freedman inequalities for martingales in the setting of noncommutative probability spaces. As an application, among other things, we provide a noncommutative Bernstein-type inequality.
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References
Accardi, L., Souissi, A., Soueidy, E.G.: Quantum Markov chains: a unification approach. Infin. Dimens. Anal. Quantum Probab. Relat. Top. 23(2), 2050016 (2020)
Araki, H.: Inequalities in von Neumann algebras, Les rencontres physiciens-mathématiciens de Strasbourg-RCP25, vol. 22 (1975). Talk no. 1
Bacry, E., Gaïffas, S., Muzy, J.-F.: Concentration inequalities for matrix martingales in continuous time. Probab. Theory Related Fields 170(1–2), 525–553 (2018)
Choi, B.J., Ji, U.C.: Exponential convergence rates for weighted sums in noncommutative probability space. Infin. Dimens. Anal. Quantum Probab. Relat. Top. 19(4), 1650027 (2016)
Choi, B.J., Ji, U.C., Lim, Y.: Inequalities for positive module operators on von Neumann algebras. J. Math. Phys. 59(6), 063513 (2018)
Cuculescu, I.: Martingales on von Neumann algebras. J. Multivar. Anal. 1, 17–27 (1971)
Fack, T., Kosaki, H.: Generalized \(s\)-numbers of \(\tau \)-measurable operators. Pac. J. Math. 123(2), 269–300 (1986)
Freedman, D.A.: On tail probabilities for martingales. Ann. Probab. 3(1), 100–118 (1975)
Harada, T., Kosaki, H.: Trace Jensen inequality and related weak majorization in semi-finite von Neumann algebras. J. Operator Theory 63, 129–150 (2010)
Jorgensen, P., Tian, F.: Non-commutative Analysis, With a Foreword by Wayne Polyzou. World Scientific Publishing Co. Pte. Ltd., Hackensack (2017)
Lévy, P.: Théorie de l’Addition des Variables Aléatoires. Gauthier-Villars, Paris (1937)
Łuczak, A.: Laws of large numbers in von Neumann algebras and related results. Studia Math. 81(3), 231–243 (1985)
Lieb, E.H.: Convex trace functions and the Wigner–Yanase–Dyson conjecture. Adv. Math. 11, 267–288 (1973)
Lin, Z., Bai, Z.D.: Probability Inequalities. Science Press, Bei**g (2010)
Nessipbayev, Y., Tulenov, K.: Non-commutative Hardy-Littlewood maximal operator on symmetric spaces of \(\tau \)-measurable operators. Ann. Funct. Anal. 12(1), Paper No. 11 (2021)
Petz, D.: A Survey of Certain Trace Inequalities, Functional Analysis and Operator Theory (Warsaw, 1992), vol. 30, pp. 287–298. Polish Acad. Sci. Inst. Math. Banach Center Publ, Warsaw (1994)
Petz, D.: Jensen’s inequality for positive contractions on operator algebras. Proc. Am. Math. Soc. 99, 273–277 (1987)
Rédei, M., Summers, S.J.: Quantum probability theory. Stud. Hist. Philos. Sci. B Stud. Hist. Philos. Modern Phys. 38(2), 390–417 (2007)
Sadeghi, Gh., Moslehian, M.S.: Noncommutative martingale concentration inequalities. Illinois J. Math. 58(2), 561–575 (2014)
Talebi, A., Moslehian, M.S., Sadeghi, Gh.: Etemadi and Kolmogorov inequalities in noncommutative probability spaces. Michigan. Math. J. 68(1), 57–69 (2019)
Tropp, J.A.: Freedman’s inequality for matrix martingales. Electron. Commun. Probab. 16, 262–270 (2011)
Wang, H., Lin, Z., Su, Z.: On Bernstein type inequalities for stochastic integrals of multivariate point processes. Stoch. Process. Appl. 129(5), 1605–1621 (2019)
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The first author is supported by a grant from the Iran National Elites Foundation (INEF) for a postdoctoral fellowship under the supervision of the third author.
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This article is part of the topical collection “Infinite-dimensional Analysis and Non-commutative Theory” edited by Marek Bozejko, Palle Jorgensen and Yuri Kondratiev.
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Talebi, A., Sadeghi, G. & Moslehian, M.S. Freedman Inequality in Noncommutative Probability Spaces. Complex Anal. Oper. Theory 16, 22 (2022). https://doi.org/10.1007/s11785-021-01186-4
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DOI: https://doi.org/10.1007/s11785-021-01186-4