- Tytuł:
- De la Vallée Poussin Summability, the Combinatorial Sum $\sum_{k=n}^{2n-1}$ (2k/k) and the de la Vallée Poussin Means Expansion
- Autorzy:
- Ali, Z. S.
- Powiązania:
- https://bibliotekanauki.pl/articles/357696.pdf
- Data publikacji:
- 2017
- Wydawca:
- Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
- Tematy:
-
complete metric space
hyperbolic space
infinite product
nonexpansive mapping
random weak ergodic property
przestrzeń metryczna całkowita
przestrzeń hiperboliczna
produkt nieskończony
mapowanie
własności ergodyczne - Opis:
- In this paper we apply the de la Vallee Poussin sum to a combinatorial Chebyshev sum by Ziad S. Ali in [1]. One outcome of this consideration is the main lemma proving the following combinatorial identity: with $Re(z)$ standing for the real part of z we have \[ \sum_{k=n}^{2n-1}\left({2k \atop k}\right) = Re\left(\left({2k \atop k}\right) \text{}_{2}F_{1}(1, 1/2 + n; 1 + n; 4\right) - \left({4n \atop 2n}\right) \text{}_{2}F_{1}(1, 1/2 + 2n; 1 + 2n; 4) \] Our main lemma will indicate in its proof that the hypergeometric factors \[ _{2}F_{1}(1, 1/2 + n; 1 + n; 4); \text{ and } _{2}F_{1}(1, 1/2 + 2n; 1 + 2n; 4) \] are complex, each having a real and imaginary part. As we apply the de la Vallee Poussin sum to the combinatorial Chebyshev sum generated in the Key lemma by Ziad S. Ali in [1], we see in the proof of the main lemma the extreme importance of the use of the main properties of the gamma function. This represents a second important consideration. A third new outcome are two interesting identities of the hypergeometric type with their new Meijer G function analogues. A fourth outcome is that by the use of the Cauchy integral formula for the derivatives we are able to give a dierent meaning to the sum: \[ \sum_{k=n}^{2n-1}\left({2k \atop k}\right) \] A fifth outcome is that by the use of the Gauss-Kummer formula we are able to make better sense of the expressions \[ \left({2n \atop n}\right)\text{}_{2}F_{1}(1, 1/2 + n; 1 + n; 4), \text{ and } \left({4n \atop 2n}\right)\text{}_{2}F_{1}(1, 1/2 + 2n; 1 + 2n; 4) \] by making use of the series denition of the hypergeometric function. As we continue we notice a new close relation of the Key lemma, and the de la Vallee Poussin means. With this close relation we were able to talk about P the de la Vallee Poussin summability of the two innite series $\sum_{n=0}^{\infty}\cos n\theta$ and $\sum_{n=0}^{\infty}(-1)^{n}\cos n\theta$. Furthermore the application of the de la Vallee Poussin sum to the Key lemma has created two new expansions representing the following functions: \[ \frac{2^{(n-1)}(1+x)^{n}(-1+2^{n}(1+x)^{n})}{n(2x+1)}, \text{ where } x=\cos \theta \] and \[ \frac {-2^{(n-1)}(-1 + 2^{n}(1-x)^{n})(1-x)^{n}} {n(2x - 1)}, \text{ where } x=\cos \theta \] in terms of the de la Vall´ee Poussin means of the two infinite series \[ \sum_{n=0}^{\infty}\cos\theta, \] and \[ \sum_{n=0}^{\infty}(-1)^{n}\cos\theta, \]
- Źródło:
-
Journal of Mathematics and Applications; 2017, 40; 5-20
1733-6775
2300-9926 - Pojawia się w:
- Journal of Mathematics and Applications
- Dostawca treści:
- Biblioteka Nauki
Artykuł