Let `1 and c denote the Banach spaces of real bounded and convergent sequences
x = (xn) normed by kxk = sup
n
jxnj ; respectively.
Let be a one to one mapping of the set of positive integers into itself such that
k
(n) =
k1
(n)
; k = 1; 2; ::: .A continuous linear functional ' on `1 is said
to be an invariant mean or a mean if and only if
(i) ' (x) 0 when xn 0 for all n;
(ii) ' (e) = 1; where e = (1; 1; 1; :::) and
(iii) '
x(n)
= ' (fxng) for all x 2 `1:
If is the translation mapping n ! n + 1; a mean is often called a Banach
limit [3], and V is the set of convergent sequences, that is, the set of bounded
sequences all of whose invariant means are equal, is the set ^f of almost convergent
sequences
Birincil Dil | İngilizce |
---|---|
Konular | Matematik |
Bölüm | Research Article |
Yazarlar | |
Yayımlanma Tarihi | 1 Şubat 2018 |
Gönderilme Tarihi | 12 Mayıs 2014 |
Yayımlandığı Sayı | Yıl 2018 Cilt: 67 Sayı: 1 |
Communications Faculty of Sciences University of Ankara Series A1 Mathematics and Statistics.
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