# Search Results

## Abstract

A certain class of stochastic summability methods of mantissa type is introduced and its connection to almost sure limit theorems is discussed. The summability methods serve as suitable weights in almost sure limit theory, covering all relevant known examples for, e.g., normalized sums or maxima of i.i.d. random variables. In the context of semistable domains of attraction the methods lead to previously unknown versions of semistable almost sure limit theorems.

In this article we prove a weak invariance principle for a strictly stationary
*φ*
-mixing sequence {
*X*
_{j}
}
_{j≧1}
, whose truncated variance function

_{n ≧1}

*φ*

^{1/2}(2

^{n}) < ∞. This will be done under the condition that

*η*

_{n}

^{2}∼

*nL*(

*η*

_{n}).

Summary An integral analogue of the general almost sure limit theorem is presented. In the theorem, instead of a sequence of random elements, a continuous time random process is involved, moreover, instead of the logarithmical average, the integral of delta-measures is considered. Then the general theorem is applied to obtain almost sure versions of limit theorems for semistable and max-semistable processes, moreover for processes being in the domain of attraction of a stable law or being in the domain of geometric partial attraction of a semistable or a max-semistable law.

## Abstract

Let X_{1},X_{2}, ... be iid random variables, and let **a**
_{n} = (*a*
_{1},*n*, ..., *a*
_{n,n}) be an arbitrary sequence of weights. We investigate the asymptotic distribution of the linear combination

*a*

_{1,n}

*X*

_{1}+ ... +

*a*

_{n,n}

*X*

_{n}under the natural negligibility condition lim

_{n→∞}max{|

*a*

_{k,n}|:

*k*= 1, ...,

*n*} = 0. We prove that if

**a**

_{n}, in which the components are of the same magnitude, then the common distribution belongs to

## Abstract

Marcinkiewicz laws of large numbers for *φ*-mixing strictly stationary sequences with *r*-th moment barely divergent, 0 < *r* < 2, are established. For this dependent analogs of the Lévy-Ottaviani-Etemadi and Hoffmann-Jørgensen inequalities are revisited.

We find a universal norming sequence in strong limit theorems for increments of sums of i.i.d. random variables with finite first moments and finite second moments of positive parts. Under various one-sided moment conditions our universal theorems imply the following results for sums and their increments: the strong law of large numbers, the law of the iterated logarithm, the Erdős-Rényi law of large numbers, the Shepp law, one-sided versions of the Csörgő-Révész strong approximation laws. We derive new results for random variables from domains of attraction of a normal law and asymmetric stable laws with index αЄ(1,2).

Let *X*
_{1}, *X*
_{2},… be independent, but not necessarily identically distributed random variables in the domain of attraction of a stable law with index 0<a<2. This paper uses *M*
_{n}=max _{1}
_{?}
_{i}
_{?}
_{n}|*X*
_{i}| to establish a self-normalized law of the iterated logarithm (LIL) for partial sums. Similarly self-normalized increments of partial sums are studied as well. In particular, the results of self-normalized sums of Horváth and Shao[9]under independent and identically distributed random variables are extended and complemented. As applications, some corresponding results for self-normalized weighted sums of iid random variables are also concluded.

## Abstract

Let *X*,*X*
_{1},*X*
_{2},… be a sequence of non-degenerate i.i.d. random variables with mean zero. The best possible weighted approximations are investigated
in *D*[0, 1] for the partial sum processes {*S*
_{[nt]}, 0 ≦ *t* ≦ 1} where *S*
_{n} = Σ_{j=1}
^{n}
*X*
_{j}, under the assumption that *X* belongs to the domain of attraction of the normal law. The conclusions then are used to establish similar results for the
sequence of self-normalized partial sum processes {*S*
_{[nt]}=*V*
_{n}, 0 ≦ *t* ≦ 1}, where *V*
_{n}
^{2} = Σ_{j=1}
^{n}
*X*
_{j}
^{2}. *L*
_{p} approximations of self-normalized partial sum processes are also discussed.

## Abstract

This paper investigates weighted approximations for Studentized *U*-statistics type processes, both with symmetric and antisymmetric kernels, only under the assumption that the distribution
of the projection variate is in the domain of attraction of the normal law. The classical second moment condition *E*|*h*(*X*
_{1}, *X*
_{2})|^{2} < ∞ is also relaxed in both cases. The results can be used for testing the null assumption of having a random sample versus
the alternative that there is a change in distribution in the sequence.