Palestine Journal of Mathematics
Vol. 5(1) (2016) , 50–58 © Palestine Polytechnic University-PPU 2016
On Generalized Statistical Convergence
Maya Altınok, Zehra Kurtdi¸ si and Mehmet Küçükaslan
Communicated by Ayman Badawi
MSC 2010 Classifications: 40A05, 40C05, 10H25.
Keywords and phrases: statistical convergence, summability of sequences, strongly summability, statistical Nörlund
convergence, weighted statistical convergence.
Abstract In this paper, statistical convergence is generalized by using regular Nörlund mean
N(p) where p =(p
n
) is a positive sequence of natural numbers. It is called statistical Nörlund
convergence and denoted by the symbol st-N(p).
Besides convergence properties of st-N(p), some inclusion results have been given between
st-N(p) convergence and strongly N(p) and statistical convergence.
Also, st-N(p) and st-N(q) convergences are compared under some certain restrictions.
1 Introduction and Backround
Statistical convergence of real (or complex) valued sequences was first introduced by Fast H. [6]
and Steinhaus I. J. [18] independently in the 1951 as a generalization of ordinary convergence.
This subject has been applied various field of mathematics by many authors such as Erdös P.-
Terenbaum G. [5], Freeedman A. R.- Sember J. J. - Raphael M. [7], etc. Besides, Connor J.[3,
4], Fridy J. A. [8], Fridy J. A.- Orhan C. [9], Salat T. [16], Schenberg I. J. [17]. Statistical
convergence is closely related to the natural density of the subset K of natural numbers N ( see
more in [2] ).
For n ∈ N, let K(n) := {k | k ≤ n, k ∈ K} for K ⊂ N. Then, the natural density (or
asymptotic density) of K ⊆ N is denoted by δ(K), and
δ(K) := lim
n→∞
1
n
n
k=1
χ
K(n)
(k) (1.1)
if this limit exists. In (1.1) the symbol χ
K(n)
(.) denotes the characteristic function of the set
K(n).
A real (or complex) sequence x =(x
n
) is said to be statistical convergent to l ∈ R (∈ C),
if the set K(ε) := {k | k ≤ n, |x
k
− l|≥ ε} has natural density zero for every ε> 0, i. e.,
δ(K(ε)) = 0. This limit is denoted by x
n
→ l(st).
Throughout this paper, let p =(p
n
) be a sequence of nonnegative natural numbers with
p
0
= 0 and p
n
> 0 for all n ∈ N and P
n
:=
∑
n
k=0
p
k
.
The Nörlund mean of the sequence x =(x
n
) is defined by t
n
:=
1
Pn
∑
n
k=1
p
n-k+1
x
k
.
The sequence x =(x
n
) is said to be N (p) convergent to l ∈ R if the sequence (t
n
)
n∈N
convergent to l ∈ R, and strongly N(p) convergence to l if
lim
n→∞
1
P
n
n
k=1
p
n-k+1
|x
k
− l| = 0.
and it is denoted by x
n
→ l (N(p)).
Definition 1.1. The sequence x =(x
n
) is said to be statistically Nörlund convergent to l if
lim
n→∞
1
P
n
n
k=1
p
n-k+1
χ
K(ε)
(k)= 0, (1.2)
holds. It is denoted by x
n
→ l (st-N(p)).
The case p
n
= 1 in Definition 1.1 is coincide with usual statistical convergence [8]. This
kind of generalization of statistical convergence has been given by Fredman and Sember in [7]
by using any regular matrix summability method.