Abstract:The aim of this paper is to provide conditions which ensure that the affinely transformed partial sums of a strictly stationary process converge in distribution to an infinite variance stable distribution. Conditions for this convergence to hold are known in the literature. However, most of these results are qualitative in the sense that the parameters of the limit distribution are expressed in terms of some limiting point process. In this paper we will be able to determine the parameters of the limiting stabl… Show more
In this article, we analyze a branching process with immigration defined recursively by
random variables independent of B t . We assume that one of generic variables A and B has a regularly varying tail distribution. We identify the tail behavior of the distribution of the stationary solution X t .We also prove CLT for the partial sums that could be further generalized to FCLT. Finally, we also show that partial maxima have a Fréchet limiting distribution.
In this article, we analyze a branching process with immigration defined recursively by
random variables independent of B t . We assume that one of generic variables A and B has a regularly varying tail distribution. We identify the tail behavior of the distribution of the stationary solution X t .We also prove CLT for the partial sums that could be further generalized to FCLT. Finally, we also show that partial maxima have a Fréchet limiting distribution.
“…Also see Embrechts et al (1997) for discussions on this topic. Recent work of Bartkiewicz, Jakubowski, Mikosch, and Wintenberger (2010), which clarifies and extends earlier work, for example Davis and Hsing (1995), provides conditions that determine the parameters of limiting distributions in terms of tail characteristics of the underlying stationary sequence. For simplicity, some conditions that we use are stronger than theirs, so as usual our conditions are sufficient but not necessary.…”
Section: Introductionmentioning
confidence: 82%
“…Assumptions A1-A4 are similar to Bartkiewicz et al (2010). Specifically, Assumption A1 is their condition RV (regular variation) restricted to the case where θ > 1 so that the expected shortfall exists.…”
We study estimation and inference of the expected shortfall for time series with infinite variance. Both the smoothed and nonsmoothed estimators are investigated. The rate of convergence is determined by the tail thickness parameter, and the limiting distribution is in the stable class with parameters depending on the tail thickness parameter of the time series and on the dependence structure, which makes inference complicated. A subsampling procedure is proposed to carry out statistical inference. We also analyze a nonparametric estimator of the conditional expected shortfall. A Monte Carlo experiment is conducted to evaluate the finite sample performance of the proposed inference procedure, and an empirical application to emerging market exchange rates (from
“…As pointed out by a referee, using the same assumptions as ours and considering α ∈ (0, 2) or α ∈ (0, 2) ∪ (2, 4), Proposition 5 in [7] expressed the limiting results in terms of characteristic functions (contrast to Lemmas 4.1(a) and 4.3(a)). The major advantage of their classical blocking and mixing techniques over the point process approach is, by controlling clustering of big values, one may calculate the parameters of the stable limit in terms of quantities of the finitedimensional distributions of the underlying process.…”
Section: Model Assumptions and Preliminariesmentioning
confidence: 91%
“…in which for α > 4, with A 1 = a + bη 2 0 and defining π := a + b, 7 7 When α > 4 and π = 0, write γ (s) = ω 2 ∞ l=0 d l d l+s and observe that γ (s) = γ (−s), K…”
Section: Theorem 33 Suppose the Assumptions In Theoremmentioning
This paper considers the short-and long-memory linear processes with GARCH (1,1) noises. The functional limit distributions of the partial sum and the sample autocovariances are derived when the tail index α is in (0, 2), equal to 2, and in (2, ∞), respectively. The partial sum weakly converges to a functional of α-stable process when α < 2 and converges to a functional of Brownian motion when α ≥ 2. When the process is of short-memory and α < 4, the autocovariances converge to functionals of α/2-stable processes; and if α ≥ 4, they converge to functionals of Brownian motions. In contrast, when the process is of long-memory, depending on α and β (the parameter that characterizes the long-memory), the autocovariances converge to either (i) functionals of α/2-stable processes; (ii) Rosenblatt processes (indexed by β, 1/2 < β < 3/4); or (iii) functionals of Brownian motions. The rates of convergence in these limits depend on both the tail index α and whether or not the linear process is short-or long-memory. Our weak convergence is established on the space of càdlàg functions on [0, 1] with either (i) the J 1 or the M 1 topology (Skorokhod, 1956); or (ii) the weaker form S topology (Jakubowski, 1997). Some statistical applications are also discussed.
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