scholarly journals Partial Sums of Generalized Class of Analytic Functions Involving Hurwitz-Lerch Zeta Function

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
G. Murugusundaramoorthy ◽  
K. Uma ◽  
M. Darus
Keyword(s):  
Analytic Function ◽  
Zeta Function ◽  
Lower Bounds ◽  
Analytic Functions ◽  
Partial Sums ◽  
Lerch Zeta Function

Letfn(z)=z+∑k=2nakzkbe the sequence of partial sums of the analytic functionf(z)=z+∑k=2∞akzk. In this paper, we determine sharp lower bounds forℜ{f(z)/fn(z)}, ℜ{fn(z)/f(z)}, ℜ{f′(z)/fn′(z)},andℜ{fn′(z)/f′(z)}. The usefulness of the main result not only provides the unification of the results discussed in the literature but also generates certain new results.

scholarly journals Partial sums and inclusion relations for analytic functions involving (p, q)-differential operator

2021 ◽  
Vol 19 (1) ◽  
pp. 329-337
Author(s):  
Huo Tang ◽  
Kaliappan Vijaya ◽  
Gangadharan Murugusundaramoorthy ◽  
Srikandan Sivasubramanian
Keyword(s):  
Analytic Function ◽  
Differential Operator ◽  
Lower Bounds ◽  
Analytic Functions ◽  
Function Class ◽  
Partial Sums ◽  
Generalized Function ◽  
Inclusion Relations ◽  
Alpha Beta

Abstract Let f k ( z ) = z + ∑ n = 2 k a n z n {f}_{k}\left(z)=z+{\sum }_{n=2}^{k}{a}_{n}{z}^{n} be the sequence of partial sums of the analytic function f ( z ) = z + ∑ n = 2 ∞ a n z n f\left(z)=z+{\sum }_{n=2}^{\infty }{a}_{n}{z}^{n} . In this paper, we determine sharp lower bounds for Re { f ( z ) / f k ( z ) } {\rm{Re}}\{f\left(z)\hspace{-0.08em}\text{/}\hspace{-0.08em}{f}_{k}\left(z)\} , Re { f k ( z ) / f ( z ) } {\rm{Re}}\{{f}_{k}\left(z)\hspace{-0.08em}\text{/}\hspace{-0.08em}f\left(z)\} , Re { f ′ ( z ) / f k ′ ( z ) } {\rm{Re}}\{{f}^{^{\prime} }\left(z)\hspace{-0.08em}\text{/}\hspace{-0.08em}{f}_{k}^{^{\prime} }\left(z)\} and Re { f k ′ ( z ) / f ′ ( z ) } {\rm{Re}}\{{f}_{k}^{^{\prime} }\left(z)\hspace{-0.08em}\text{/}\hspace{-0.08em}{f}^{^{\prime} }\left(z)\} , where f ( z ) f\left(z) belongs to the subclass J p , q m ( μ , α , β ) {{\mathcal{J}}}_{p,q}^{m}\left(\mu ,\alpha ,\beta ) of analytic functions, defined by Sălăgean ( p , q ) \left(p,q) -differential operator. In addition, the inclusion relations involving N δ ( e ) {N}_{\delta }\left(e) of this generalized function class are considered.

Certain classes of analytic functions defined by Hurwitz–Lerch zeta function

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bolineni Venkateswarlu ◽  
Pinninti Thirupathi Reddy ◽  
Galla Swapna ◽  
Rompilli Madhuri Shilpa
Keyword(s):  
Zeta Function ◽  
Unit Disk ◽  
Analytic Functions ◽  
Partial Sums ◽  
Open Unit ◽  
Open Unit Disk ◽  
Coefficient Estimates ◽  
New Class ◽  
Lerch Zeta Function

Abstract In this work, we introduce and investigate a new class k - U ⁢ S ~ s ⁢ ( b , μ , γ , t ) {k-\widetilde{US}_{s}(b,\mu,\gamma,t)} of analytic functions in the open unit disk U with negative coefficients. The object of the present paper is to determine coefficient estimates, neighborhoods and partial sums for functions f belonging to this class.

scholarly journals Partial Sums For Class Of Analytic Functions Defined By Integral Operator

2014 ◽  
Vol 8 (4) ◽  
Author(s):  
Nagat. M. Mustafa ◽  
Maslina Darus
Keyword(s):  
Integral Operator ◽  
Zeta Function ◽  
Analytic Functions ◽  
Partial Sums ◽  
Its Sequence ◽  
Coefficient Estimates ◽  
Lerch Zeta Function

In the present paper, we study the class of analytic functions involving generalized integral operator, which is defined by means of a general Hurwitz Lerch Zeta function denoted by ,()sbfzαℑwith negative coefficients. The aim of the paper is to obtain the coefficient estimates and also partial sums of its sequence ,()

scholarly journals Some local-convexity theorems for the zeta-function-like analytic functions

1988 ◽  
Vol Volume 11 ◽  
Author(s):  
R Balasubramanian ◽  
K Ramachandra
Keyword(s):  
Lower Bound ◽  
Zeta Function ◽  
Lower Bounds ◽  
Exponential Function ◽  
Riemann Zeta Function ◽  
Analytic Functions ◽  
Local Convexity ◽  
The Riemann Zeta Function ◽  
International Audience ◽  
Riemann Zeta

International audience In this paper we investigate lower bounds for $$I(\sigma)= \int^H_{-H}\vert f(\sigma+it_0+iv)\vert^kdv,$$ where $f(s)$ is analytic for $s=\sigma+it$ in $\mathcal{R}=\{a\leq\sigma\leq b, t_0-H\leq t\leq t_0+H\}$ with $\vert f(s)\vert\leq M$ for $s\in\mathcal{R}$. Our method rests on a convexity technique, involving averaging with the exponential function. We prove a general lower bound result for $I(\sigma)$ and give an application concerning the Riemann zeta-function $\zeta(s)$. We also use our methods to prove that large values of $\vert\zeta(s)\vert$ are ``rare'' in a certain sense.

scholarly journals New Result of Analytic Functions Related to Hurwitz Zeta Function

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
F. Ghanim ◽  
M. Darus
Keyword(s):  
Analytic Function ◽  
Linear Operator ◽  
Zeta Function ◽  
Analytic Functions ◽  
Hadamard Product ◽  
Hurwitz Zeta Function

By using a linear operator, we obtain some new results for a normalized analytic functionfdefined by means of the Hadamard product of Hurwitz zeta function. A class related to this function will be introduced and the properties will be discussed.

scholarly journals ON DISCRETE UNIVERSALITY OF COMPOSITE FUNCTIONS

2012 ◽  
Vol 17 (2) ◽  
pp. 271-280 ◽  
Author(s):  
Jovita Rašytė
Keyword(s):  
Analytic Function ◽  
Zeta Function ◽  
Riemann Zeta Function ◽  
Analytic Functions ◽  
Space Of Analytic Functions ◽  
Composite Functions ◽  
The Riemann Zeta Function ◽  
Fixed Positive Number ◽  
Riemann Zeta ◽  
Discrete Universality

In 1975, S.M. Voronin proved that the Riemann zeta-function ζ (s) is universal in the sense that its shifts approximate uniformly on some sets any analytic function. Let h be a fixed positive number such that exp is irrational for all . In the paper, the classes of functions F such that the shifts F (ζ (s + imh)), , approximate any analytic function are presented. For the proof of theorems, some elements of the space of analytic functions are applied.

HANKEL DETERMINANT FOR CERTAIN SUBCLASS OF ANALYTIC FUNCTIONS ASSOIATED WITH GENERALIZED SRIVASTAVA–ATTIYA OPERATOR

2020 ◽  
Vol 3 (1) ◽  
pp. 1-9
Author(s):  
Somaya Mohammed Alkabaily ◽  
Nagat Muftah Alabbar
Keyword(s):  
Zeta Function ◽  
Upper Bound ◽  
Analytic Functions ◽  
Hankel Determinant ◽  
Lerch Zeta Function ◽  
Second Hankel Determinant

This paper is to introduce a certain class of analytic functions denoted by  which is defined by generalized Srivastava – Attiya operator. This operator is associated with Hurwitz-Lerch Zeta function, obtain an upper bound to the second Hankel determinant  for  the class .

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