A simple note on some empirical stochastic process as a tool in uniform L-statistics weak laws

TL;DR

This paper studies a stochastic process related to empirical distribution functions and L-Statistics, providing theoretical results on moments, covariance, and conditions for asymptotic tightness, useful for understanding time-dependent statistical laws.

Contribution

It offers a detailed analysis of a stochastic process used in L-Statistics, including moment calculations and tightness conditions, extending existing literature.

Findings

Derived explicit formulas for the first moments.

Calculated the covariance function of the process.

Established conditions for asymptotic tightness.

Abstract

In this paper, we are concerned with the stochastic process \begin{equation} \beta_{n}(q_{t},t)=\beta_{n}(t)=\frac{1}{\sqrt{n}}\sum_{j=1}^{n}\left\{G_{t,n}(Y(t))-G_{t}(Y_{j}(t))\right\} q_{t}(Y_{j}(t)), \tag{A} \end{equation} where for $n\geq1$ and $T>0$, the sequences $\{Y_{1}(t),Y_{2}(t),...,Y_{n}(t),t\in [0,T]\}$ are independant observations of some real stochastic process ${Y(t),t\in [0,T]}$, for each $t \in [0,T]$, $G_{t}$ is the distribution function of $% Y(t)$ and $G_{t,n}$ is the empirical distribution function based on $% Y_{1}(t),Y_{2}(t),...,Y_{n}(t)$, and finally $q_{t}$ is a bounded real fonction defined on $\mathbb{R}$. This process appears when investigating some time-dependent L-Statistics which are expressed as a function of some functional empirical process and the process (A). Since the functional empirical process is widely investigated in the literature, the process reveals itself as an important key for L-Statistics laws. In this paper, we state an extended study of this process, give complete calculations of the first moments, the covariance function and find conditions for asymptotic tightness.