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Abstract
In this paper, we introduce a new class of analytic functions defined by a new
convolution operator Js,a,λ
(λp),(μq),b which generalizes the well-known Srivastava-Attiya
operator investigated by Srivastava and Attiya (Integral Transforms Spec. Funct.
18:207-216, 2007). We derive coefficient inequalities, distortion theorems, extreme
points and the Fekete-Szegö problem for this new function class.
MSC: Primary 30C45; 11M35; secondary 30C10
Results & Lemmas (3)
Each result is auto-extracted from the paper via OCR - the math is shown verbatim and may carry occasional transcription artifacts. Click to expand the full statement.
Theorem 1 · coeff
Theorem 1. Let. If satisfies the following equality then Proof Suppose that inequality (2.1) holds for. Let us define the function F(z) by…
Theorem 1. Let $\alpha \in [0,1)$ . If $f(z) \in A$ satisfies the following equality
$$\sum_{k=2}^{\infty} \frac{(k-\alpha)}{k!} \left| \frac{\prod_{j=1}^{p} (\lambda_j + 1)_{k-1}}{\prod_{j=1}^{q} (\mu_j + 1)_{k-1}} \right| \left| \left( \frac{a+1}{a+k} \right)^s \right| \left| \left( \frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)} \right) \right| |a_k| \le 1 - \alpha, \tag{2.1}$$
then
$$f \in \mathcal{S}^{s,a,\lambda,*}_{(\lambda_p),(\mu_q),b}(\alpha).$$
Proof Suppose that inequality (2.1) holds for $\alpha \in [0,1)$ . Let us define the function F(z) by
$$F(z) := \frac{z(J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda})'(f)(z)}{J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(f)(z)} - \alpha \quad (f(z) \in \mathcal{A}).$$
$$(2.2)$$
It is sufficient to prove that
$$\left| \frac{F(z) - 1}{F(z) + 1} \right| < 1 \quad (z \in \mathbb{U}) \tag{2.3}$$
to prove that $f(z) \in \mathcal{S}^{s,a,\lambda,*}_{(\lambda_p),(\mu_q),b}(\alpha)$ .
In fact, we have that
$$\begin{split} \left| \mathcal{F}(z) \right| &:= \left| \frac{F(z) - 1}{F(z) + 1} \right| = \left| \frac{\frac{z(J_{\lambda p}^{S,A,\lambda}(\mu_q),b}^{S,A,\lambda}(f)(z)}{J_{(\lambda p),(\mu_q),b}^{S,a,\lambda}(f)(z)} - \alpha - 1}{\frac{z(J_{\lambda p}^{S,A,\lambda}(\mu_q),b}^{S,a,\lambda}(f)(z))}{J_{(\lambda p),(\mu_q),b}^{S,a,\lambda}(f)(z)} - \alpha + 1} \right| \\ &= \left| \frac{\alpha z + \sum_{k=2}^{\infty} \frac{\prod_{j=1}^{p} (\lambda_j + 1)_{k-1}}{\prod_{j=1}^{q} (\mu_j + 1)_{k-1}} (\frac{a + 1}{a + k})^s (\frac{\Lambda(a + k, b, s, \lambda)}{\Lambda(a + 1, b, s, \lambda)}) \frac{(\alpha + 1 - k)}{k!} a_k z^k}{(2 - \alpha) z - \sum_{k=2}^{\infty} \frac{\prod_{j=1}^{p} (\lambda_j + 1)_{k-1}}{\prod_{j=1}^{q} (\mu_j + 1)_{k-1}} (\frac{a + 1}{a + k})^s (\frac{\Lambda(a + k, b, s, \lambda)}{\Lambda(a + 1, b, s, \lambda)}) \frac{(\alpha - 1 - k)}{k!} a_k z^k} \right|, \end{split}$$
and thus
$$\begin{split} \left| \mathcal{F}(z) \right| & \leq \frac{\alpha |z| + \sum_{k=2}^{\infty} |\frac{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}}{\prod_{j=1}^{p} (\mu_{j} + 1)_{k-1}} ||(\frac{a+1}{a+k})^{s}||(\frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)})||\frac{(\alpha+1-k)}{k!}||a_{k}| \cdot |z|^{k}}{(2-\alpha)|z| - \sum_{k=2}^{\infty} |\frac{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}}{\prod_{j=1}^{q} (\mu_{j} + 1)_{k-1}} ||(\frac{a+1}{a+k})^{s}||(\frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)})||\frac{(\alpha-1-k)}{k!}||a_{k}| \cdot |z|^{k}} \\ & < \frac{\alpha + \sum_{k=2}^{\infty} |\frac{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}}{\prod_{j=1}^{q} (\mu_{j} + 1)_{k-1}} ||(\frac{a+1}{a+k})^{s}||(\frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)})||\frac{(k-\alpha-1)}{k!}|a_{k}|}{(2-\alpha) - \sum_{k=2}^{\infty} |\frac{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}}{\prod_{j=1}^{q} (\mu_{j} + 1)_{k-1}} ||(\frac{a+1}{a+k})^{s}||(\frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)})||\frac{(k-\alpha+1)}{k!}|a_{k}|} \leq 1, \end{split}$$
provided that (2.1) is satisfied.
The next theorem aims to provide coefficient inequalities for functions f(z) belonging to the class $\mathcal{S}^{s,a,\lambda,*}_{(\lambda_p),(\mu_q),b}(\alpha)$ .
Theorem 2 · coeff
Theorem 2. Let. If, then The result is sharp. Proof Let Then p(z) is analytic and and. We note easily that With the help of (1.17), we find…
Theorem 2. Let $\alpha \in [0,1)$ . If $f(z) \in S^{s,a,\lambda,*}_{(\lambda_n),(\mu_a),b}(\alpha)$ , then
$$|a_{k}| \leq k! \left(\frac{2(1-\alpha)}{k-1}\right) \left| \left(\frac{a+k}{a+1}\right)^{s} \right| \left| \left(\frac{\Lambda(a+1,b,s,\lambda)}{\Lambda(a+k,b,s,\lambda)}\right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}} \right| \prod_{j=2}^{k-1} \left(1 + \frac{2(1-\alpha)}{j-1}\right) \quad (k \in \mathbb{N} \setminus \{1\}).$$
$$(2.4)$$
The result is sharp.
Proof Let
$$p(z) := \frac{\frac{z(f_{(\lambda_p),(\mu_q),b}^{s,a,\lambda})'(f)(z)}{f_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(f)(z)} - \alpha}{1 - \alpha} = 1 + c_1 z + c_2 z^2 + \cdots$$
Then p(z) is analytic and
$$p(0) = 1$$
and $\Re(p(z)) > 0$ $(z \in \mathbb{U})$ .
We note easily that
$$z\left(J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}\right)'(f)(z) = \left[(1-\alpha)p(z) + \alpha\right]J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(f)(z).$$
With the help of (1.17), we find
$$\frac{(k-1)}{k!} \frac{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}}{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}} \left(\frac{a+1}{a+k}\right)^{s} \left(\frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)}\right) a_{k}$$
$$= (1-\alpha) \cdot \left[c_{k-1} + \sum_{m=2}^{k-1} \frac{\prod_{j=1}^{p} (\lambda_{j}+1)_{m-1}}{\prod_{j=1}^{q} (\mu_{j}+1)_{m-1}} \left(\frac{a+1}{a+m}\right)^{s} \left(\frac{\Lambda(a+m,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)}\right) \frac{a_{m}c_{k-m}}{m!}\right] (2.5)$$
for $k \in \mathbb{N} \setminus \{1\}$ .
By making use of the Carathéodory lemma [29, p.41], we have
$$\frac{(k-1)}{k!} \left| \frac{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}}{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}} \right| \left| \left( \frac{a+1}{a+k} \right)^{s} \right| \left| \left( \frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)} \right) \right| \cdot |a_{k}| \\
\leq 2(1-\alpha) \\
\cdot \left[ 1 + \sum_{m=2}^{k-1} \left| \frac{\prod_{j=1}^{p} (\lambda_{j}+1)_{m-1}}{\prod_{j=1}^{q} (\mu_{j}+1)_{m-1}} \right| \left| \left( \frac{a+1}{a+m} \right)^{s} \right| \left| \left( \frac{\Lambda(a+m,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)} \right) \left| \frac{|a_{m}|}{m!} \right| \right|. \tag{2.6}$$
We have to prove that inequality (2.4) holds true for $k \in \mathbb{N} \setminus \{1\}$ . We will proceed by the principle of mathematical induction. If k = 2 in (2.6), we obtain
$$|a_{2}| \leq 4(1-\alpha) \left| \frac{\prod_{j=1}^{q} (\mu_{j}+1)}{\prod_{j=1}^{p} (\lambda_{j}+1)} \right| \left| \left( \frac{a+2}{a+1} \right)^{s} \right| \left| \left( \frac{\Lambda(a+1,b,s,\lambda)}{\Lambda(a+2,b,s,\lambda)} \right) \right|.$$
(2.7)
Now suppose that (2.4) is satisfied for $k \le n$ . Then, from (2.4) and (2.6), we have that
$$\frac{n}{(n+1)!} \left| \frac{\prod_{j=1}^{p} (\lambda_{j}+1)_{n}}{\prod_{j=1}^{q} (\mu_{j}+1)_{n}} \right| \left( \frac{a+1}{a+n+1} \right)^{s} \left| \left( \frac{\Lambda(a+n+1,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)} \right) \right| \cdot |a_{n+1}| \\
\leq 2(1-\alpha) \left[ 1 + \sum_{m=2}^{n} \left| \frac{\prod_{j=1}^{p} (\lambda_{j}+1)_{m-1}}{\prod_{j=1}^{q} (\mu_{j}+1)_{m-1}} \right| \left( \frac{a+1}{a+m} \right)^{s} \right| \left( \frac{\Lambda(a+m,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)} \right) \left| \frac{|a_{m}|}{m!} \right] \\
\leq 2(1-\alpha) \left[ 1 + \sum_{m=2}^{n} \frac{2(1-\alpha)}{m-1} \prod_{j=2}^{m-1} \left( 1 + \frac{2(1-\alpha)}{j-1} \right) \right] \\
\leq 2(1-\alpha) \prod_{j=2}^{n} \left( 1 + \frac{2(1-\alpha)}{j-1} \right), \tag{2.8}$$
whence
$$|a_{k}| \leq k! \left(\frac{2(1-\alpha)}{k-1}\right) \left| \left(\frac{a+k}{a+1}\right)^{s} \right| \left| \left(\frac{\Lambda(a+1,b,s,\lambda)}{\Lambda(a+k,b,s,\lambda)}\right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}} \right| \prod_{j=2}^{k-1} \left(1 + \frac{2(1-\alpha)}{j-1}\right) \quad (k \in \mathbb{N} \setminus \{1\}).$$
The result is sharp for the function f(z) given by
$$f(z) = z + \frac{2(1-\alpha)}{k-1} \left(\frac{a+k}{a+1}\right)^{s} \left(\frac{\Lambda(a+1,b,s,\lambda)}{\Lambda(a+k,b,s,\lambda)}\right) \cdot \frac{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}} \prod_{j=2}^{k-1} \left(1 + \frac{2(1-\alpha)}{j-1}\right) z^{k} \quad (k \in \mathbb{N} \setminus \{1\}).$$
Theorem 3
Theorem 3. Let and. Then and (3.2) Proof Let be given by (1.1). Then, making use of Theorem 2, we find (3.3) and (3.4) From (1.1), we also…
Theorem 3. Let $f(z) \in \mathcal{S}^{s,a,\lambda,*}_{(\lambda_p),(\mu_q),b}(\alpha)$ and $0 \leq \alpha < 1$ . Then
$$r - 2(1 - \alpha)r^{2} \sum_{k=2}^{\infty} \frac{k!}{k-1} \left| \left( \frac{a+k}{a+1} \right)^{s} \right| \left| \left( \frac{\Lambda(a+1,b,s,\lambda)}{\Lambda(a+k,b,s,\lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}} \right| \prod_{j=2}^{k-1} \left( 1 + \frac{2(1-\alpha)}{j-1} \right)$$
$$\leq |f(z)|$$
$$\leq r + 2(1-\alpha)r^{2} \sum_{k=2}^{\infty} \frac{k!}{k-1} \left| \left( \frac{a+k}{a+1} \right)^{s} \right| \left| \left( \frac{\Lambda(a+1,b,s,\lambda)}{\Lambda(a+k,b,s,\lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}} \right| \prod_{j=2}^{k-1} \left( 1 + \frac{2(1-\alpha)}{j-1} \right) \quad (|z| = r < 1)$$
$$(3.1)$$
and
$$1 - 2(1 - \alpha)r \sum_{k=2}^{\infty} \frac{k \cdot k!}{k - 1} \left| \left( \frac{a + k}{a + 1} \right)^{s} \right| \left| \left( \frac{\Lambda(a + 1, b, s, \lambda)}{\Lambda(a + k, b, s, \lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j} + 1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}} \right| \prod_{j=2}^{k-1} \left( 1 + \frac{2(1 - \alpha)}{j - 1} \right)$$
$$\leq \left| f'(z) \right|$$
$$\leq 1 + 2(1 - \alpha)r \sum_{k=2}^{\infty} \frac{k \cdot k!}{k - 1} \left| \left( \frac{a + k}{a + 1} \right)^{s} \right| \left| \left( \frac{\Lambda(a + 1, b, s, \lambda)}{\Lambda(a + k, b, s, \lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j} + 1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}} \right| \prod_{j=2}^{k-1} \left( 1 + \frac{2(1 - \alpha)}{j - 1} \right) \quad (|z| = r < 1).$$
(3.2)
Proof Let $f(z) \in A$ be given by (1.1). Then, making use of Theorem 2, we find
$$|f(z)| \leq |z| + \sum_{k=2}^{\infty} |a_k| \cdot |z^k|$$
$$\leq r + 2(1 - \alpha)r^2 \sum_{k=2}^{\infty} \frac{k!}{k - 1} \left| \left( \frac{a + k}{a + 1} \right)^s \right| \left| \left( \frac{\Lambda(a + 1, b, s, \lambda)}{\Lambda(a + k, b, s, \lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^q (\mu_j + 1)_{k-1}}{\prod_{j=1}^p (\lambda_j + 1)_{k-1}} \right| \prod_{j=2}^{k-1} \left( 1 + \frac{2(1 - \alpha)}{j - 1} \right) \quad (|z| = r < 1)$$
(3.3)
and
$$|f(z)| \geq |z| - \sum_{k=2}^{\infty} |a_{k}| \cdot |z^{k}|$$
$$\geq r - 2(1 - \alpha)r^{2} \sum_{k=2}^{\infty} \frac{k!}{k-1} \left| \left( \frac{a+k}{a+1} \right)^{s} \right| \left| \left( \frac{\Lambda(a+1,b,s,\lambda)}{\Lambda(a+k,b,s,\lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}} \right| \prod_{j=2}^{k-1} \left( 1 + \frac{2(1-\alpha)}{j-1} \right) \quad (|z| = r < 1).$$
(3.4)
From (1.1), we also have that
$$|f'(z)| \leq 1 + \sum_{k=2}^{\infty} k \cdot |a_{k}| \cdot |z^{k-1}|$$
$$\leq 1 + 2(1 - \alpha)r \sum_{k=2}^{\infty} \frac{k \cdot k!}{k - 1} \left| \left( \frac{a + k}{a + 1} \right)^{s} \right| \left| \left( \frac{\Lambda(a + 1, b, s, \lambda)}{\Lambda(a + k, b, s, \lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j} + 1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}} \right| \prod_{i=2}^{k-1} \left( 1 + \frac{2(1 - \alpha)}{j - 1} \right) \quad (|z| = r < 1)$$
(3.5)
and
$$|f'(z)| \ge 1 - \sum_{k=2}^{\infty} k \cdot |a_{k}| \cdot |z^{k}|$$
$$\ge 1 - 2(1 - \alpha)r \sum_{k=2}^{\infty} \frac{k \cdot k!}{k - 1} \left| \left( \frac{a + k}{a + 1} \right)^{s} \right| \left| \left( \frac{\Lambda(a + 1, b, s, \lambda)}{\Lambda(a + k, b, s, \lambda)} \right) \right|$$
$$\cdot \left| \frac{\prod_{j=1}^{q} (\mu_{j} + 1)_{k-1}}{\prod_{j=1}^{p} (\lambda_{j} + 1)_{k-1}} \right| \prod_{i=2}^{k-1} \left( 1 + \frac{2(1 - \alpha)}{j - 1} \right) \quad (|z| = r < 1).$$
(3.6)
We thus obtain the results (3.1) and (3.2) asserted by Theorem 3.
Definitions (2)
Def 1
Definition 1. The H-function involved in the right-hand side of (1.7) is the well-known Fox's H-function [15, Definition 1.1] (see also…
Definition 1. The H-function involved in the right-hand side of (1.7) is the well-known Fox's H-function [15, Definition 1.1] (see also [14, 16]) defined by
$$H_{\mathfrak{p},\mathfrak{q}}^{m,n}(z) = H_{\mathfrak{p},\mathfrak{q}}^{m,n} \left[ z \mid (a_{1},A_{1}),\dots,(a_{\mathfrak{p}},A_{\mathfrak{p}}) \right]$$
$$= \frac{1}{2\pi i} \int_{C} \Xi(s)z^{-s} \, ds \quad (z \in \mathbb{C} \setminus \{0\}; |\arg(z)| < \pi), \tag{1.9}$$
where
$$\Xi(s) = \frac{\prod_{j=1}^{m} \Gamma(b_j + B_j s) \cdot \prod_{j=1}^{n} \Gamma(1 - a_j - A_j s)}{\prod_{j=n+1}^{p} \Gamma(a_j + A_j s) \cdot \prod_{j=m+1}^{q} \Gamma(1 - b_j - B_j s)},$$
an empty product is interpreted as 1, m, n, $\mathfrak{p}$ and $\mathfrak{q}$ are integers such that $1 \le m \le \mathfrak{q}$ , $0 \le n \le \mathfrak{p}$ , $A_j > 0$ $(j = 1, ..., \mathfrak{p})$ , $B_j > 0$ $(j = 1, ..., \mathfrak{q})$ , $a_j \in \mathbb{C}$ $(j = 1, ..., \mathfrak{p})$ , $b_j \in \mathbb{C}$ $(j = 1, ..., \mathfrak{q})$ and $\mathcal{L}$ is a suitable Mellin-Barnes type contour separating the poles of the gamma functions
$$\left\{\Gamma(b_j+B_js)\right\}_{j=1}^m$$
from the poles of the gamma functions
$$\left\{\Gamma(1-a_j+A_js)\right\}_{j=1}^n.$$
It is worthy to mention that using the fact that [8, p.1496, Remark 7]
$$\lim_{b \to 0} \left\{ H_{0,2}^{2,0} \left[ (a+n)b^{\frac{1}{\lambda}} \mid \overline{(s,1), \left(0, \frac{1}{\lambda}\right)} \right] \right\} = \lambda \Gamma(s) \quad (\lambda > 0), \tag{1.10}$$
equation (1.7) reduces to
$$\Phi_{\lambda_{1},...,\lambda_{p};\mu_{1},...,\mu_{q}}^{(\rho_{1},...,\rho_{p},\sigma_{1},...,\sigma_{q})}(z,s,a;0,\lambda) := \Phi_{\lambda_{1},...,\lambda_{p};\mu_{1},...,\mu_{q}}^{(\rho_{1},...,\rho_{p},\sigma_{1},...,\sigma_{q})}(z,s,a)$$
$$= \sum_{n=0}^{\infty} \frac{\prod_{j=1}^{p} (\lambda_{j})_{n\rho_{j}}}{(a+n)^{s} \cdot \prod_{i=1}^{q} (\mu_{j})_{n\sigma_{i}}} \frac{z^{n}}{n!}.$$
(1.11)
Def 2
Definition 2. The function involved in (1.11) is the multiparameter extension and generalization of the Hurwitz-Lerch zeta function…
Definition 2. The function $\Phi_{\lambda_1,\ldots,\lambda_p;\mu_1,\ldots,\mu_q}^{(\rho_1,\ldots,\rho_p,\sigma_1,\ldots,\sigma_q)}(z,s,a)$ involved in (1.11) is the multiparameter extension and generalization of the Hurwitz-Lerch zeta function $\Phi(z,s,a)$ introduced by Srivastava et al. [13, p.503, Eq. (6.2)] defined by
$$\begin{split} &\Phi_{\lambda_{1},\ldots,\lambda_{p};\mu_{1},\ldots,\mu_{q}}^{(\rho_{1},\ldots,\rho_{p},\sigma_{1},\ldots,\sigma_{q})}(z,s,a):=\sum_{n=0}^{\infty}\frac{\prod_{j=1}^{p}(\lambda_{j})_{n\rho_{j}}}{(a+n)^{s}\cdot\prod_{j=1}^{q}(\mu_{j})_{n\sigma_{j}}}\frac{z^{n}}{n!}\\ &\left(p,q\in\mathbb{N}_{0};\lambda_{j}\in\mathbb{C}\;(j=1,\ldots,p);a,\mu_{j}\in\mathbb{C}\setminus\mathbb{Z}_{0}^{-}\;(j=1,\ldots,q);\\ &\rho_{j},\sigma_{k}\in\mathbb{R}^{+}\;(j=1,\ldots,p;k=1,\ldots,q); \end{split}$$
$\Delta > -1$ when $s, z \in \mathbb{C}$ ;
$\Delta = -1$ and $s \in \mathbb{C}$ when $|z| < \nabla^*$ ;
$$\Delta = -1 \text{ and } \Re(\Xi) > \frac{1}{2} \text{ when } |z| = \nabla^*$$
(1.12)
with
$$\nabla^* := \left(\prod_{j=1}^p \rho_j^{-\rho_j}\right) \cdot \left(\prod_{j=1}^q \sigma_j^{\sigma_j}\right),\tag{1.13}$$
$$\Delta := \sum_{j=1}^{q} \sigma_j - \sum_{j=1}^{p} \rho_j \quad \text{and} \quad \Xi := s + \sum_{j=1}^{q} \mu_j - \sum_{j=1}^{p} \lambda_j + \frac{p-q}{2}. \tag{1.14}$$
We propose to consider the following linear operator
$$J^{s,a,\lambda}_{(\lambda_p),(\mu_q),b}(f): \mathcal{A} \to \mathcal{A},$$
defined by
$$J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(f)(z) = G_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(z) * f(z),$$
(1.15)
where \* denotes the Hadamard product (or convolution) of analytic functions, and the function $G^{s,a,\lambda}_{(\lambda_p),(\mu_q),b}(z)$ is given by
$$G_{(\lambda_{p}),(\mu_{q}),b}^{s,a,\lambda}(z) := \frac{\lambda \prod_{j=1}^{q} (\mu_{j}) \Gamma(s)(a+1)^{s}}{\prod_{j=1}^{p} (\lambda_{j})} \cdot \Lambda(a+1,b,s,\lambda)^{-1} \cdot \left[ \Phi_{\lambda_{1},\dots,\lambda_{p};\mu_{1},\dots,\mu_{q}}^{(1,\dots,1,1,\dots,1)}(z,s,a;b,\lambda) - \frac{a^{-s}}{\lambda \Gamma(s)} \Lambda(a,b,s,\lambda) \right]$$
$$= z + \sum_{k=2}^{\infty} \frac{\prod_{j=1}^{p} (\lambda_{j}+1)_{k-1}}{\prod_{j=1}^{q} (\mu_{j}+1)_{k-1}} \left( \frac{a+1}{a+k} \right)^{s} \left( \frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)} \right) \frac{z^{k}}{k!}$$
$$(1.16)$$
with
$$\Lambda(a,b,s,\lambda) := H_{0,2}^{2,0} \left[ ab^{\frac{1}{\lambda}} \mid \overline{(s,1), \left(0,\frac{1}{\lambda}\right)} \right].$$
Combining (1.15) and (1.16), we obtain
$$J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(f)(z)$$
$$= z + \sum_{k=2}^{\infty} \frac{\prod_{j=1}^{p} (\lambda_j + 1)_{k-1}}{\prod_{j=1}^{q} (\mu_j + 1)_{k-1}} \left(\frac{a+1}{a+k}\right)^s \left(\frac{\Lambda(a+k,b,s,\lambda)}{\Lambda(a+1,b,s,\lambda)}\right) a_k \frac{z^k}{k!}$$
$$(\lambda_j \in \mathbb{C} \ (j=1,\ldots,p) \text{ and } \mu_j \in \mathbb{C} \setminus \mathbb{Z}_0^- \ (j=1,\ldots,q); p \leq q+1; z \in \mathbb{U}), \tag{1.17}$$
with
$$\min\{\Re(a),\Re(s)\}>0;$$
$\lambda>0$ if $\Re(b)>0$
and
$$s \in \mathbb{C}$$
; $a \in \mathbb{C} \setminus \mathbb{Z}_0^-$ if $b = 0$ .
Remark 1 It follows from (1.15) and (1.17) that the operator $J_{(\lambda_p),(\mu_q),0}^{s,a,\lambda}(f)$ (special case of (1.17) when b=0) can be defined for $a \in \mathbb{C} \setminus \mathbb{Z}^-$ by the following limit relationship:
$$J_{(\lambda_p),(\mu_q),0}^{s,0,\lambda}(f)(z) := \lim_{a \to 0} \left\{ J_{(\lambda_p),(\mu_q),0}^{s,a,\lambda}(f)(z) \right\}. \tag{1.18}$$
We can see that the operator $J^{s,a,\lambda}_{(\lambda_p),(\mu_q),b}$ generalizes several recently investigated operators such as:
- (i) If p = 2, q = 1 and b = 0, then $J_{(\lambda_1, \lambda_2), (\mu_1), 0}^{s,a,\lambda} = J_{\lambda_1, \lambda_2; \mu_1}^{s,a}$ , where $J_{\lambda_1, \lambda_2; \mu_1}^{s,a}$ is the linear operator introduced by Prajapat and Bulboacă [17, p.571, Eq. (1.8)].
- (ii) $J_{(\gamma-1,1),(\nu),0}^{s,a,\lambda} = I_{a,\nu,\gamma}^{s}$ , where $I_{a,\nu,\gamma}^{s}$ is the generalized operator recently studied by Noor and Bukhari [18, p.2, Eq. (1.3)].
- (iii) $J_{(\gamma-1,1),(\nu),0}^{0,0,\lambda} = I_{\nu,\gamma}^s$ , where $I_{\nu,\gamma}^s$ is the Choi-Saigo-Srivastava operator [19].
- (iv) $J_{(\gamma,1),(\gamma),0}^{s,a,\lambda} = J_{s,a}$ , where $J_{s,a}$ is the Srivastava-Attiya operator [1].
- (v) $J_{(\gamma,1),(\gamma),0}^{-r,a,\lambda} = I(r,a)$ ( $a \ge 0$ , $r \in \mathbb{Z}$ ), where the operator I(r,a) is the one introduced by Cho and Srivastava [20].
- (vi) $J_{(\beta,1),(\alpha+\beta),0}^{0,a,\lambda} = \mathcal{Q}^{\alpha}_{\beta}$ ( $\alpha \geq 0$ , $\beta > -1$ ), where the operator $\mathcal{Q}^{\alpha}_{\beta}$ was studied by Jung et al. [21].
- (vii) $J_{(\gamma,1),(\gamma),0}^{1,a,\lambda} = J_a$ ( $a \ge -1$ ), where $J_a$ denotes the Bernardi operator [22].
- (viii) $J_{(\gamma,1),(\nu),0}^{0,0,\lambda} = \mathcal{L}(\gamma,\nu)$ , where $\mathcal{L}(\gamma,\nu)$ is the well-known Carlson-Shaffer operator [23].
- (ix) $J_{(2,1),(2-\gamma),0}^{0,0,\lambda} = \Omega_z^{\gamma}$ ( $0 \le \gamma < 1$ ), where $\Omega_z^{\gamma}$ is the fractional integral operator investigated by Owa and Srivastava [24].
- (x) $J_{(\lambda_1-1,\ldots,\lambda_p-1,1),(\mu_1-1,\ldots,\mu_q-1,0),0}^{0,a,\lambda}=H_1(\lambda_1,\ldots,\lambda_p;\mu_1,\ldots,\mu_q)$ ( $p\leq q+1$ ), where the operator $H_1(\lambda_1,\ldots,\lambda_p;\mu_1,\ldots,\mu_q)$ is the Dziok-Srivastava operator [25, 26] which contains as special cases the Hohlov operator [27] and the Ruscheweyh operator [28].
We say that a function $f \in \mathcal{A}$ is in the class $\mathcal{S}^{s,a,\lambda,}_{(\lambda_p),(\mu_q),b}(\alpha)$ if $J^{s,a,\lambda}_{(\lambda_p),(\mu_q),b}(f)$ is in the class $\mathcal{S}^(\alpha)$ , that is, if
$$\Re\left(\frac{z(J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(f))'}{J_{(\lambda_p),(\mu_q),b}^{s,a,\lambda}(f)}\right) > \alpha$$
$$\left(\lambda_j \in \mathbb{C} \ (j=1,\ldots,p) \text{ and } \mu_j \in \mathbb{C} \setminus \mathbb{Z}_0^- \ (j=1,\ldots,q);$$
$$z \in \mathbb{U}; 0 \leq \alpha < 1; p \leq q+1\right), \tag{1.19}$$
with
$$\min\{\Re(a),\Re(s)\}>0;$$
$\lambda>0$ if $\Re(b)>0$
and
$$s \in \mathbb{C}$$
; $a \in \mathbb{C} \setminus \mathbb{Z}^-$ if $b = 0$ .
In this paper, we systematically investigate the class $\mathcal{S}^{s,a,\lambda,*}_{(\lambda_p),(\mu_q),b}(\alpha)$ of analytic functions defined above by means of the new generalized Srivastava-Attiya convolution operator $J^{s,a,\lambda}_{(\lambda_p),(\mu_q),b}$ . Especially, we derive coefficient inequalities, distortion theorems, extreme points and the Fekete-Szegö problem for this new function class.
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