# Wydawnictwa / Czasopisma IMPAN / Studia Mathematica / Wszystkie zeszyty

## On the statistical and $\sigma$-cores

### Tom 154 / 2003

Studia Mathematica 154 (2003), 29-35 MSC: Primary 40C05; Secondary 26A03, 11B05. DOI: 10.4064/sm154-1-3

#### Streszczenie

In [11] and [7], the concepts of $\sigma$-core and statistical core of a bounded number sequence $x$ have been introduced and also some inequalities which are analogues of Knopp's core theorem have been proved. In this paper, we characterize the matrices of the class $(S \cap m, V_{\sigma })_{{\rm reg}}$ and determine necessary and sufficient conditions for a matrix $A$ to satisfy $\sigma$-core$(Ax) \subseteq {}$st-core$(x)$ for all $x \in m$.

#### Autorzy

• Hüsamettın Çoşkunİnönü Üniversitesi
Eğitim Fakültesi
44100-Malatya, Turkey
e-mail
• Celal Çakanİnönü Üniversitesi
Eğitim Fakültesi
44100-Malatya, Turkey
e-mail
• MursaleenDepartment of Mathematics
Aligarh Muslim University
Aligarh-202-002, India
e-mail

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