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15 August 2023

New Results about Fuzzy Differential Subordinations Associated with Pascal Distribution

and
1
Department of Mathematics, Faculty of Science, Damietta University, New Damietta 34517, Egypt
2
Department of Mathematics, Technical University of Cluj-Napoca, 400114 Cluj-Napoca, Romania
*
Author to whom correspondence should be addressed.
Current address: Department of Mathematics, College of Science and Arts, Al-Badaya, Qassim University, Buraidah 52571, Saudi Arabia.

Abstract

Based upon the Pascal distribution series N q , λ r , m Υ ( ζ ) : = ζ + j = m + 1 j + r 2 r 1 1 + λ ( j 1 ) q j 1 ( 1 q ) r a j ζ j , we can obtain a set of fuzzy differential subordinations in this investigation. We also newly obtain class P q , λ F , r , m η of univalent analytic functions defined by the operator N q , λ r , m , give certain properties for the class P q , λ F , r , m η and also obtain some applications connected with a special case for the operator. New research directions can be taken on fuzzy differential subordinations associated with symmetry operators.

1. Introduction

Let H m ( ϖ ) represent the class of holomorphic and univalent functions on ϖ such that ϖ C and let H ( ϖ ) denote the class of holomorphic functions on ϖ . The class of holomorphic functions in the open unit disk of the complex plane Λ = { ζ C : ζ < 1 } is denoted in this study by a note H ( Λ ) , with B Λ = { ζ C : ζ = 1 } standing as the unit disk’s boundary. For m N = 1 , 2 , , we define
H m γ = Υ H ( Λ ) : Υ ( ζ ) = γ + j = m + 1 a j ζ j , ζ Λ ,
A m = Υ H ( Λ ) : Υ ( ζ ) = ζ + j = m + 1 a j ζ j , ζ Λ with A 1 = A ,
and
S = Υ A m : Υ is a univalent function in Λ .
We denote by
C = Υ A m : 1 + ζ Υ ( ζ ) Υ ( ζ ) > 0 , ζ Λ ,
which is the set of convex functions on Λ .
Let Υ 1 and Υ 2 be analytic in Λ . Then Υ 1 is subordinate to Υ 2 written as Υ 1 Υ 2 if there exists a Schwarz function ϕ , which is analytic in Λ with ϕ ( 0 ) = 0 and ϕ ζ < 1 for all ζ Λ such that Υ 1 ( ζ ) = Υ 2 ( ϕ ζ ) . Furthermore, if the function Υ 2 is univalent in Λ , then we have the following equivalence (see [1,2]):
Υ 1 ( ζ ) Υ 2 ( ζ ) Υ 1 ( 0 ) = Υ 2 ( 0 ) and Υ 1 ( Λ ) Υ 2 ( Λ ) .
In order to introduce the notion of fuzzy differential subordination, we use the following definitions and propositions:
Definition 1
([3]). Assume that T is a Fuzzy subset and F : T 0 , 1 is an application. A pair of Λ , F Λ , where F Λ : T 0 , 1 , and
R = x T : 0 < F Λ ( x ) 1 = sup Λ , F Λ ,
a fuzzy subset. The fuzzy set Λ , F Λ is called a function F Λ .
Let Υ , g H ( ϖ ) be denoted by
Υ ϖ = Υ ( ζ ) : 0 < F Υ ϖ Υ ( ζ ) 1 , ζ ϖ = sup Υ ϖ , F Υ ϖ ,
and
g ϖ = g ( ζ ) : 0 < F g ϖ g ( ζ ) 1 , ζ ϖ = sup g ϖ , F g ϖ .
Proposition 1
([4]). (i) If B , F B = U , F U , then we have B = U , where B = sup B , F B and U = sup U , F U ; ( i i ) if B , F B U , F U , then we have B U , where B = sup B , F B and U = sup U , F U .
Definition 2
([4]). Let ζ 0 ϖ be a fixed point and let the functions Υ , g H ( ϖ ) . The function Υ is said to be fuzzy subordinate to g, and we write Υ F g or Υ ( ζ ) F g ( ζ ) , which satisfies the following conditions:
(i) 
Υ ( ζ 0 ) = g ( ζ 0 ) ;
(ii) 
F Υ ϖ Υ ( ζ ) F g ϖ g ( ζ ) , ζ ϖ .
Proposition 2
([4]). Assume that ζ 0 ω is a fixed point and the functions Υ , g H ( ω ) . If Υ ( ζ ) F g ( ζ ) , ζ ω , then
(i) 
Υ ( ζ 0 ) = g ( ζ 0 )
(ii) 
Υ ω g ω , F Υ ω Υ ( ζ ) F g ω g ( ζ ) , ζ ω ,
where Υ ω and g ω are defined by (2) and (3), respectively.
Definition 3
([5]). Assume that h S and Φ : C 3 × Λ C , Φ α , 0 , 0 ; 0 = h ( 0 ) = α . If p satisfies the requirements of the second-order fuzzy differential subordination and is analytic in Λ, with p ( 0 ) = α ,
F Φ ( C 3 × Λ ) Φ p ( ζ ) , ζ p ( ζ ) , ζ 2 p ( ζ ) ; ζ F h Λ h ( ζ ) .
If q is a fuzzy dominant of the fuzzy differential subordination solutions, then p is said to be a fuzzy solution of the fuzzy differential subordination and satisfies
F p Λ p ( ζ ) F q Λ q ( ζ ) , i . e . , p ( ζ ) F q ( ζ ) , ζ Λ ,
for each and every p satisfying (4).
Definition 4.
A fuzzy dominant q ˜ that satisfies
F q ˜ Λ q ˜ ( ζ ) F q Λ q ( ζ ) ,
then
q ˜ ( ζ ) F q ( ζ ) , ζ Λ .
The fuzzy best dominant of (4) is referred to for all fuzzy dominants.
Assume the function Ω A m is given by
Ω ( ζ ) : = ζ + j = m + 1 ψ j ζ j , ζ Λ .
The Hadamard (or convolution) product of Υ and Ω is defined as
( Υ Ω ) ( ζ ) : = ζ + j = m + 1 a j ψ j ζ j , ζ Λ .
A variable x is said to have the Pascal distribution if it takes the values 0 , 1 , 2 , 3 , with the probabilities ( 1 q ) r , q r ( 1 q ) r 1 ! , q 2 r ( r + 1 ) ( 1 q ) r 2 ! , q 3 r ( r + 1 ) ( r + 2 ) ( 1 q ) r 3 ! , …, respectively, where q and r are called the parameters, and thus we have the probability formula
P ( X = k ) = k + r 1 r 1 q k ( 1 q ) r , k N 0 = N 0 .
Now we present a power series whose coefficients are Pascal distribution probabilities, i.e.,
Q q , m r ( ζ ) : = ζ + j = m + 1 j + r 2 r 1 q j 1 ( 1 q ) r ζ j , ζ Λ , m N , r 1 , 0 q 1 .
We easily determine from the ratio test that the radius of convergence of the above power series is at least 1 q 1 ; hence, Q q , m r A m .
We define the functions
M q , λ r , m ( ζ ) : = ( 1 λ ) Q q , m r ( ζ ) + λ z Q q , m r ( ζ ) = ζ + j = m + 1 j + r 2 r 1 1 + λ ( j 1 ) q j 1 ( 1 q ) r ζ j , ζ Λ , m N , r 1 , 0 q 1 , λ 0 .
El-Deeb and Bulboacă [6] introduced the linear operator N q , λ r , m : A m A m defined by
N q , λ r , m Υ ( ζ ) : = M q , λ r , m ( ζ ) Υ ( ζ ) = ζ + j = m + 1 j + r 2 r 1 1 + λ ( j 1 ) q j 1 ( 1 q ) r a j ζ j , ζ Λ , m N , r 1 , 0 q 1 , λ 0 ,
where Υ is given by (1), and the symbol “*” stands for the Hadamard (or convolution) product.
Remark 1.
(i) For m = 1 , the operator N q , λ r , m reduces to I q , λ r : = N q , λ r , 1 , introduced and studied by El-Deeb et al. [7]; (ii) for m = 1 and λ = 0 , the operator Q q r reduces to Q q r : = N q , 0 r , 1 , introduced and studied by El-Deeb et al. [7].
Using the operator N q , λ r , m , we create a class of analytical functions and derive several fuzzy differential subordinations for this class.
Definition 5.
If the function Υ A belongs to the class P q , λ F , r , m η for all η 0 , 1 and satisfies the inequality
F N q , λ r , m Υ Λ N q , λ r , m Υ ( ζ ) > η , ζ Λ .

2. Preliminary

The following lemmas are needed to show our results.
Lemma 1
([2]). Assume that Ϝ A and G ( ζ ) = 1 ζ 0 ζ Ϝ ( t ) d t , ζ Λ . If 1 + ζ Ϝ ( ζ ) Ϝ ( ζ ) > 1 2 , ζ Λ , then G C .
Lemma 2
(Theorem 2.6 in [8]). If Ϝ is a convex function such that Ϝ ( 0 ) = γ , ν C = C { 0 } with ν 0 . If p H m γ such that p ( 0 ) = γ , Φ : C 2 × Λ C , Φ p ( ζ ) , ζ p ( ζ ) ; ζ = p ( ζ ) + 1 ν ζ p ( ζ ) is an analytic function in Λ and
F Φ ( C 2 × Λ ) p ( ζ ) + 1 ν ζ p ( ζ ) F h Λ h ( ζ ) p ( ζ ) + 1 ν ζ p ( ζ ) F h ( ζ ) , ζ Λ ,
then
F p Λ p ( ζ ) F q Λ q ( ζ ) F h Λ h ( ζ ) p ( ζ ) F q ( ζ ) , ζ Λ ,
where
q ( ζ ) = ν m ζ ν m 0 ζ ψ ( t ) t ν m 1 d t , ζ Λ .
The function q is convex, and it is the fuzzy best dominant.
Lemma 3
(Theorem 2.7 in [8]). Let g be a convex function in Λ and Ϝ ( ζ ) = g ( ζ ) + m γ ζ g ( ζ ) , where ζ Λ , m N and γ > 0 , if
p ( ζ ) = g ( 0 ) + p m ζ m + p m + 1 ζ m + 1 + . . . H ( Λ ) ,
and
F p ( Λ ) p ( ζ ) + γ ζ p ( ζ ) F ψ Λ ψ ( ζ ) p ( ζ ) + γ ζ p ( ζ ) F ψ ( ζ ) , ζ Λ .
Then
F p ( Λ ) p ( ζ ) F g Λ g ( ζ ) p ( ζ ) F g ( ζ ) , ζ Λ .
This result is sharp.
We define the fuzzy differential subordination general theory and its applications (see [9,10,11,12,13]). The method of fuzzy differential subordination is applied in the next section to obtain a set of fuzzy differential subordinations related to the operator N q , λ r , m .

3. Main Results

Assume that η 0 , 1 , m N , r 1 , 0 q 1 , λ 0 and ζ Λ are mentioned throughout this paper.
Theorem 1.
Let k belong to C in Λ, and h ( ζ ) = k ( ζ ) + 1 ρ + 2 ζ k ( ζ ) . If Υ P q , λ F , r , m η and
G ( ζ ) = I ρ Υ ( ζ ) = ρ + 2 ζ ρ + 1 0 ζ t ρ Υ ( t ) d t ,
then
F N q , λ r , m Υ Λ N q , λ r , m Υ ( ζ ) F h Λ h ( ζ ) N q , λ r , m Υ ( ζ ) F h ( ζ ) ,
implies
F N q , λ r , m G Λ N q , λ r , m G ( ζ ) F k Λ k ( ζ ) N q , λ r , m G ( ζ ) F k ( ζ ) .
Proof. 
Since
ζ ρ + 1 G ( ζ ) = ρ + 2 0 ζ t ρ Υ ( t ) d t ,
by differentiating, we obtain
ρ + 1 G ( ζ ) + ζ G ( ζ ) = ρ + 2 Υ ( ζ ) ,
and
ρ + 1 N q , λ r , m G ( ζ ) + ζ N q , λ r , m G ( ζ ) = ρ + 2 N q , λ r , m Υ ( ζ ) ,
and also, by differentiating (7), we obtain
N q , λ r , m G ( ζ ) + 1 ρ + 2 ζ N q , λ r , m G ( ζ ) = N q , λ r , m Υ ( ζ ) .
The fuzzy differential subordination (6) technique is used
F N q , λ r , m Υ Λ N q , λ r , m G ( ζ ) + 1 ρ + 2 ζ N q , λ r , m G ( ζ )
F h Λ k ( ζ ) + 1 ρ + 2 ζ k ( ζ ) .
We denote
q ( ζ ) = N q , λ r , m G ( ζ ) , so q H 1 n .
Putting (10) in (9), we have
F N q , λ r , m Υ Λ q ( ζ ) + 1 ρ + 2 ζ q ( ζ ) F h Λ k ( ζ ) + 1 ρ + 2 ζ k ( ζ ) .
Using Lemma (3), we obtain
F q Λ q ( ζ ) F k Λ k ( ζ ) , i . e . F N q , λ r , m G ( ζ ) Λ N q , λ r , m G ( ζ ) F k Λ k ( ζ ) ,
and therefore, N q , λ r , m G ( ζ ) F k ( ζ ) , where k is the fuzzy best dominant. □
Putting m = 1 and λ = 0 in Theorem 1, we obtain the following example since the operator Q q r reduces to Q q r : = N q , 0 r , 1 .
Example 1.
Let k be an element of C in Λ and h ( ζ ) = k ( ζ ) + 1 ρ + 2 ζ k ( ζ ) . If Υ P q , λ F , r , m η and G is given by (5), then
F Q q r Υ Λ Q q r Υ ( ζ ) F h Λ h ( ζ ) Q q r Υ ( ζ ) F h ( ζ ) ,
implies
F Q q r G Λ Q q r G ( ζ ) F k Λ k ( ζ ) Q q r G ( ζ ) F k ( ζ ) .
Theorem 2.
Assume that h ( ζ ) = 1 + 2 η 1 ζ 1 + ζ , η 0 , 1 , λ > 0 and I ρ is given by (5), then
I ρ P q , λ F , r , m η P q , λ F , r , m η ,
where
η = 2 η 1 + ρ + 2 2 2 η 0 1 t ρ + 2 t + 1 dt .
Proof. 
A function h belongs to C , and we obtain from the hypothesis of Theorem 2 using the same technique as that in the proof of Theorem 1 that
F q Λ q ( ζ ) + 1 ρ + 2 ζ q ( ζ ) F h Λ h ( ζ ) ,
where q ( ζ ) is defined in (10). By using Lemma 2, we obtain
F q Λ q ( ζ ) F k Λ k ( ζ ) F h Λ h ( ζ ) ,
which implies
F N q , λ r , m G Λ N q , λ r , m G ( ζ ) F k Λ k ( ζ ) F h Λ h ( ζ ) ,
where
k ( ζ ) = ρ + 2 ζ ρ + 2 0 ζ t ρ + 1 1 + 2 η 1 t 1 + t d t = 2 η 1 + ρ + 2 2 2 η ζ ρ + 2 0 ζ t ρ + 1 1 + t d t C ,
where k Λ is symmetric with respect to the real axis, so we have
F N q , λ r , m G Λ N q , λ r , m G ( ζ ) min ζ = 1 F k Λ k ( ζ ) = F k Λ k ( 1 ) ,
and η = k ( 1 ) = 2 η 1 + ρ + 2 2 2 η 0 1 t ρ + 2 t + 1 d t .
Theorem 3.
Assume that k belongs to C in Λ, that k ( 0 ) = 1 , and that h ( ζ ) = k ( ζ ) + ζ k ( ζ ) . When Υ A and the fuzzy differential subordination is satisfied,
F N q , λ r , m Υ Λ N q , λ r , m Υ ( ζ ) F h Λ h ( ζ ) N q , λ r , m Υ ( ζ ) F h ( ζ ) ,
holds, then
F N q , λ r , m Υ Λ N q , λ r , m Υ ζ ζ F k Λ k ( ζ ) N q , λ r , m Υ ζ ζ F k ( ζ ) .
Proof. 
Let
q ( ζ ) = N q , λ r , m Υ ζ ζ = ζ + j = m + 1 j + r 2 r 1 1 + λ ( j 1 ) q j 1 ( 1 q ) r a j ζ j ζ = 1 + j = m + 1 j + r 2 r 1 1 + λ ( j 1 ) q j 1 ( 1 q ) r a j ζ j 1 ,
and we obtain that
q ( ζ ) + ζ q ( ζ ) = N q , λ r , m Υ ζ ,
so
F N q , λ r , m Υ Λ N q , λ r , m Υ ( ζ ) F h Λ h ( ζ )
implies
F q Λ q ( ζ ) + ζ q ( ζ ) F h Λ h ( ζ ) = F k Λ k ( ζ ) + ζ k ( ζ ) .
Using the Lemma 3, we obtain
F q Λ q ( ζ ) F k Λ k ( ζ ) F N q , λ r , m Υ Λ N q , λ r , m Υ ζ ζ F k Λ k ( ζ ) ,
and we obtain
N q , λ r , m Υ ζ ζ F k ( ζ ) .
Theorem 4.
Consider h H ( Λ ) , which satisfies 1 + ζ h ( ζ ) h ( ζ ) > 1 2 when h ( 0 ) = 1 . If the fuzzy differential subordination
F N q , λ r , m Υ Λ N q , λ r , m Υ ( ζ ) F h Λ h ( ζ ) N q , λ r , m Υ ( ζ ) F h ( ζ ) ,
then
F N q , λ r , m Υ Λ N q , λ r , m Υ ζ ζ F k Λ k ( ζ ) i . e . N q , λ r , m Υ ζ ζ F k ( ζ ) ,
where
k ( ζ ) = 1 ζ 0 ζ h ( t ) dt ,
the function k is convex, and it is the fuzzy best dominant.
Proof. 
Let
q ( ζ ) = N q , λ r , m Υ ζ ζ = 1 + j = d + 1 [ j ] q ! [ λ + 1 ] q , j 1 a j ψ j ζ j 1 , q H 1 1 ,
where 1 + ζ h ( ζ ) h ( ζ ) > 1 2 . From Lemma 1, we have
k ( ζ ) = 1 ζ 0 ζ h ( t ) d t
belongs to the class C , which satisfies the fuzzy differential subordination (17). Since
k ( ζ ) + ζ k ( ζ ) = h ( ζ ) ,
it is the fuzzy best dominant. We have
q ( ζ ) + ζ q ( ζ ) = N q , λ r , m Υ ζ ,
then (17) becomes
F q Λ q ( ζ ) + ζ q ( ζ ) F h Λ h ( ζ ) .
By using Lemma 3, we obtain
F q Λ q ( ζ ) F k Λ k ( ζ ) , i . e . F N q , λ r , m Υ Λ N q , λ r , m Υ ζ ζ F k Λ k ( ζ ) ,
then
N q , λ r , m Υ ζ ζ F k ( ζ ) .
Putting h ( ζ ) = 1 + 2 υ 1 ζ 1 + ζ in Theorem 4. As a result, we have the following corollary:
Corollary 1.
Let h = 1 + 2 υ 1 ζ 1 + ζ be a convex function in Λ, with h ( 0 ) = 1 , 0 β < 1 . If Υ A and verifies the fuzzy differential subordination
F N q , λ r , m Υ Λ N q , λ r , m Υ ( ζ ) F h Λ 1 + 2 υ 1 ζ 1 + ζ , i . e . N q , λ r , m Υ ( ζ ) F 1 + 2 υ 1 ζ 1 + ζ ,
then
F N q , λ r , m Υ Λ N q , λ r , m Υ ζ ζ F k Λ k ( ζ ) ,
then
N q , λ r , m Υ ζ ζ F k ( ζ ) ,
where
k ( ζ ) = 2 υ 1 + 2 1 υ ζ ln 1 + ζ ,
the function k is convex and it is the fuzzy best dominant.
Putting m = 1 and λ = 0 in Corollary 1, we obtain the following example.
Example 2.
Let h = 1 + 2 υ 1 ζ 1 + ζ be a convex function in Λ, with h ( 0 ) = 1 , 0 β < 1 . If f A and verifies the fuzzy differential subordination
F Q q r Υ Λ Q q r Υ ( ζ ) F h Λ 1 + 2 υ 1 ζ 1 + ζ , i . e . Q q r Υ ( ζ ) F 1 + 2 υ 1 ζ 1 + ζ
then
F Q q r Υ Λ Q q r Υ ζ ζ F k Λ k ( ζ ) i . e . Q q r Υ ζ ζ F k ( ζ ) ,
where
k ( ζ ) = 2 υ 1 + 2 1 υ ζ ln 1 + ζ .

4. Conclusions

All of the above results provide information about fuzzy differential subordinations for the operator N q , λ r , m ; we also provide certain properties for the class P q , λ F , r , m η of univalent analytic functions. Using these classes and operators, we can create some simple applications.

Author Contributions

Conceptualization, S.M.E.-D. and L.-I.C.; Formal analysis, S.M.E.-D. and L.-I.C.; Investigation, S.M.E.-D. and L.-I.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

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