Martingale convergence theorem in quantum logics
Martingale Hardy spaces and BMO spaces generated by an operator T are investigated. An atomic decomposition of the space is given if the operator T is predictable. We generalize the John-Nirenberg theorem, namely, we prove that the spaces generated by an operator T are all equivalent. The sharp operator is also considered and it is verified that the norm of the sharp operator is equivalent to the norm. The interpolation spaces between the Hardy and BMO spaces are identified by the real method....
The purpose of this paper is to investigate moderate deviations for the Durbin–Watson statistic associated with the stable first-order autoregressive process where the driven noise is also given by a first-order autoregressive process. We first establish a moderate deviation principle for both the least squares estimator of the unknown parameter of the autoregressive process as well as for the serial correlation estimator associated with the driven noise. It enables us to provide a moderate deviation...
Consider the sequence of positive numbers defined by C₁ = 1 and , n = 1,2,.... Let M be a real-valued martingale and let S(M) denote its square function. We establish the bound |Mₙ|≤ Cₙ Sₙ(M), n=1,2,..., and show that for each n, the constant Cₙ is the best possible.
We obtain sharp bounds for the monotonic rearrangement operator from "dyadic-type" classes to "continuous" ones; in particular, for the BMO space and Muckenhoupt classes. The idea is to connect the problem with a simple geometric construction named α-extension.