• Title/Summary/Keyword: summability

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On Classical Studies for Summability and Convergence of Double Fourier Series (이중 푸리에 급수의 총합가능성과 수렴성에 대한 고전적인 연구들에 관하여)

  • Lee, Jung Oh
    • Journal for History of Mathematics
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    • v.27 no.4
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    • pp.285-297
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    • 2014
  • G. H. Hardy laid the foundation of classical studies on double Fourier series at the beginning of the 20th century. In this paper we are concerned not only with Fourier series but more generally with trigonometric series. We consider Norlund means and Cesaro summation method for double Fourier Series. In section 2, we investigate the classical results on the summability and the convergence of double Fourier series from G. H. Hardy to P. Sjolin in the mid-20th century. This study concerns with the $L^1(T^2)$-convergence of double Fourier series fundamentally. In conclusion, there are the features of the classical results by comparing and reinterpreting the theorems about double Fourier series mutually.

On (H, μn) Summability of Fourier Series

  • CHANDRA, SATISH
    • Kyungpook Mathematical Journal
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    • v.43 no.4
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    • pp.513-518
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    • 2003
  • In this paper, we have proved a theorem on Hausdorff summability of Fourier series which generalizes various known results. We prove that if $${\int}_{o}^{t}\;{\mid}{\phi}(u){\mid}\;du=o(t)\;as\;t{\rightarrow}0\; and\;\lim_{n{\rightarrow}{\infty}}{\int}^{\eta}_{{\pi}/n}{\frac{{\mid}{\phi}(t)-{\phi}(t+{\pi}/n){\mid}}{t}}dt=o(n)$$ where 0 < ${\eta}$ < 1, then the Fourier series is (H, ${\mu}_n$) summable to s at t = x where the sequence ${\mu}_n$ is given by ${\mu}_n={\int}^1_0x^n{\chi}(x)\;dx\;n=0,1,2\;and\;K_n(t)=\limits\sum_{{\nu}=0}^n(\array {n\\{\nu}})({\Delta}^{{n}-{\nu}}{\mu}_{\nu}){\frac{sin{\nu}t}{t}}$.

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A Generalization of Abel's Theorem on Power Series

  • Hsiang, W.H.
    • The Mathematical Education
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    • v.29 no.1
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    • pp.55-61
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    • 1990
  • There are three objectives of this paper. First, we present an elegant and simple generalization of Abel's theorem (i .e. tile Abel summability (on the unit disk of the euclidean plane) is regular). Second, we consider the definition of Abel summability through lim (equation omitted) which immediately has clear connexctions with CeSARO summability and Cesaro sums (equation omitted). This approach examplifies some simple aspects of so-called Tauberian theorems of divergent series. Third, we present the applications of the previous results to find the limits of transition probabilities of homogeneous Marker chain. Finally, we explain why the original Abel's theorem which looks obvious is difficult to be proved, and can not be proved analytically.

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DEGREE OF APPROXIMATION OF A FUNCTION ASSOCIATED WITH HARDY-LITTLEWOOD SERIES IN WEIGHTED ZYGMUND W(Z(𝜔)r)-CLASS USING EULER-HAUSDORFF SUMMABILITY MEANS

  • Tejaswini Pradhan;G V V Jagannadha Rao
    • Nonlinear Functional Analysis and Applications
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    • v.28 no.4
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    • pp.1035-1049
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    • 2023
  • Approximation of functions of Lipschitz and Zygmund classes have been considered by various researchers under different summability means. In the proposed study, we investigated an estimation of the order of convergence of a function associated with Hardy-Littlewood series in the weighted Zygmund class W(Z(𝜔)r)-class by applying Euler-Hausdorff summability means and subsequently established some (presumably new) results. Moreover, the results obtained here represent the generalization of several known results.

ALTERNATE SIGNS AVERAGING PROPERTIES IN BANACH SPACES

  • Cho, Kyug-Eun;Lee, Chong-Sung
    • Journal of applied mathematics & informatics
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    • v.16 no.1_2
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    • pp.497-507
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    • 2004
  • In this paper, we first seek the equivalent statements with averaging properties in terms of the regular summability method, secondly define some new averaging properties and study their implications. Finally, we investigate the question of what property is dual to the Banach-Saks property suggested by C. Seifert.

On Deferred Statistical Convergence of Sequences

  • Kucukaslan, Mehme;Yilmazturk, Mujde
    • Kyungpook Mathematical Journal
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    • v.56 no.2
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    • pp.357-366
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    • 2016
  • In this paper, deferred statistical convergence is defined by using deferred $Ces{\grave{a}}ro$ mean instead of $Ces{\grave{a}}ro$ mean in the definition of statistical convergence. The obtained method is compared with strong deferred $Ces{\grave{a}}ro$ mean and statistical convergence under some certain assumptions. Also, some inclusion theorems and examples are given.

DOUBLE WIJSMAN LACUNARY STATISTICAL CONVERGENCE OF ORDER 𝛼

  • GULLE, ESRA;ULUSU, UGUR
    • Journal of applied mathematics & informatics
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    • v.39 no.3_4
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    • pp.303-319
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    • 2021
  • In this paper, we introduce the concepts of Wijsman strongly p-lacunary summability of order 𝛼, Wijsman lacunary statistical convergence of order 𝛼 and Hausdorff lacunary statistical convergence of order 𝛼 for double set sequences. Also, we investigate some properties of these new concepts and examine the existence of some relationships between them. Furthermore, we study the relationships between these new concepts and some concepts in the literature.

LACUNARY STATISTICAL CONVERGENCE FOR SEQUENCE OF SETS IN INTUITIONISTIC FUZZY METRIC SPACE

  • KISI, OMER
    • Journal of applied mathematics & informatics
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    • v.40 no.1_2
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    • pp.69-83
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    • 2022
  • We investigate the concept of lacunary statistical convergence and lacunary strongly convergence for sequence of sets in intuitionistic fuzzy metric space (IFMS) and examine their characterization. We obtain some inclusion relation relating to these concepts. Further some necessary and sufficient conditions for equality of the sets of statistical convergence and lacunary statistical convergence for sequence of sets in IFMS have been established. The concept of strong Cesàro summability in IFMS has been defined and some results are established.

ON LACUNARY ∆m-STATISTICAL CONVERGENCE IN G-METRIC SPACES

  • Asif Hussain Jan;Tanweer Jalal
    • Korean Journal of Mathematics
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    • v.32 no.1
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    • pp.109-120
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    • 2024
  • The aim of this research is to describe lacunary ∆m-statistically convergent sequences with respect to metrics on generalised metric spaces (g-metric spaces) and to look into the fundamental characteristics of this statistical form of convergence. Also, the relationship between strong summability and lacunary ∆m-statistical convergence in g-metric space is established at the end.