Study on subclasses of analytic functionsActa Univ. Sapientiae, Mathematica, 9, 1 (2017) 122{139...

Acta Univ. Sapientiae, Mathematica, 9, 1 (2017) 122–139

DOI: 10.1515/ausm-2017-0008

Study on subclasses of analytic functions

Imran FaisalDepartment of Mathematics,

University of Education, Pakistanemail: [email protected]

Maslina DarusSchool of Mathematical Sciences,

Faculty of Science and Technology,Universiti Kebangsaan Malaysia,

Malaysiaemail: [email protected]

Abstract. By making use of new linear fractional differential operator,we introduce and study certain subclasses of analytic functions associ-ated with Symmetric Conjugate Points and defined in the open unit diskU = z : |z| < 1. Inclusion relationships are established and convolutionproperties of functions in these subclasses are discussed.

1 Introduction and preliminaries

Let A denote the class of functions of the form

f(z) = z+

∞∑k=2

akzk, (1)

which are analytic in the open unit disk U = z : |z| < 1 and normalized byf(0) = f ′(0) − 1 = 0.

A function f ∈ A is called starlike if and only if

<

(zf ′(z)

f(z)

)≥ 0, (z ∈ U).

2010 Mathematics Subject Classification: 30C45Key words and phrases: starlike functions, symmetric conjugate points, inclusion rela-tionships

122

Study on subclasses of analytic functions 123

The class of starlike functions is denoted by S.A function f ∈ A is called convex if and only if

<

(1+

zf ′′(z)

f ′(z)

)≥ 0, (z ∈ U).

The class of convex functions is denoted by K.A function f ∈ A is called starlike of order ρ if and only if

<

(zf ′(z)

f(z)

)≥ ρ, (ρ > 0, z ∈ U). (2)

The class of starlike functions of order ρ is denoted by SV?(ρ).Similarly a function f ∈ A is called convex of order ρ if and only if

<

(1+

zf ′′(z)

f ′(z)

)≥ ρ, (ρ > 0, z ∈ U). (3)

The class of starlike functions of order ρ is denoted by KV(ρ).It follows from (2) and (3) that f ∈ KV(ρ) if and only if zf ′(z) ∈ SV?(ρ).Let f ∈ A and g ∈ SV?(ρ), then f ∈ A is called close-to-convex of order θ

and type ρ if and only if

<

(zf ′(z)

g(z)

)≥ θ, (0 ≤ θ, ρ < 1, z ∈ U).

The class of close-to-convex of order θ and type ρ is denoted by CV(θ, ρ).In 1959, Sakaguchi [1] introduced the following class of analytic functions:A function f ∈ A is called starlike with respect to symmetrical points, and

its class is denoted by SVs, if it satisfies the analytic criterion

<

(zf ′(z)

f(z) − f(−z)

)> 0, (z ∈ U).

For more details we refer to study Shanmugam et al. [2], Chand and Singh [3]and Das and Singh [4] respectively.

In 1987, El-Ashwah and Thomas [5] introduced the following class of analyticfunctions:

A function f ∈ A is called starlike with respect to symmetric conjugatepoints, and its class is denoted by SVsc, if it satisfies the analytic criterion

<

(zf ′(z)

f(z) − f(−z)

)> 0, (z ∈ U).

124 I. Faisal, M. Darus

For two functions f and g analytic in U, we say that the function f issubordinate to g in U and write

f(z) ≺ g(z) (z ∈ U),

if there exists a Schwarz function w(z) which (by definition) is analytic in Uwith

w(0) = 0 and |w(z)| < 1,

such that

f(z) = g(w(z)) z ∈ U.

Indeed it is known that

f(z) ≺ g(z) z ∈ U⇒ f(0) = g(0) and f(U) ⊂ g(U).

Furthermore, if the function g is univalent in U, then we have the followingequivalence:

f(z) ≺ g(z) z ∈ U⇔ f(0) = g(0) and f(U) ⊂ g(U).

For functions f(z) = z+∞∑k=2

akzk and g(z) = z+

∞∑k=2

bkzk the Hadamard product

(or convolution) f ∗ g is defined as usual by

(f ∗ g)(z) = z+∞∑k=2

akbkzk.

Let

ϕ(a, c; z) = z2F(1, a; c; z) =

∞∑k=0

(a)k(c)k

zk−1, (z ∈ U; c 6= 0,−1,−2, .s),

where (a)k is the pochhammer symbol defined by

(a)k =Γ(k+ a)

Γ(a)=

1 if k = 0a(a+ 1)(a+ 2).s(a+ k− 1) if k ∈ N

.

In 1987, Owa and Srivastava [7] introduced the operator as follow

Ωαf(z) = Γ(2− α)zαDαz f(z) = ϕ(2, 2− α; z) ∗ f(z),α 6= 2, 3, 4, . . . . (4)


Also note that Ω0f(z) = f(z) and Dαz f(z) is the fractional derivative of orderα given in [6].

For f ∈ A, we define the linear fractional differential operator as follow:

I0,νλ (α,β, µ)f(z) = f(z)

I1,νλ (α,β, µ)f(z) =

(ν− µ+ β− λ

ν+ β

)Ωαf(z) +

(µ+ λ

ν+ β

)z(Ωαf(z)) ′

I2,νλ (α,β, µ)f(z) = Iαλ (I1,νλ (α,β, µ)f(z))

...

In,νλ (α,β, µ)f(z) = Iαλ (In−1,νλ (α,β, µ)f(z)) .

(5)

If f(z) is given by (1) then from (5) we have

In,νλ (α,β, µ)f(z)

= z+

∞∑k=2

((Γ(k+ 1)Γ(2− α)

Γ(k+ 1− α)

)(ν+ (µ+ λ)(k− 1) + β

ν+ β

))nakz

k.(6)

Using (4) we conclude that

In,νλ (α,β, µ)f(z) = [ϕ(2, 2− α; z) ∗ gµ,νβ,λ(z).sϕ(2, 2− α; z) ∗ gµ,νβ,λ(z)]︸︷︷︸ ∗f(z), (7)

where

gµ,νβ,λ(z) =

z−(ν−µ+β−λν+β

)z2

(1− z)2

=

(z−

ν− µ+ β− λ

ν+ βz2)(1+ 2z+ 3z2 + · · · )

= z+

(1+

µ+ λ

ν+ β

)z2 +

(1+ 2

µ+ λ

ν+ β

)z3 + · · ·

...

gµ,νβ,λ(z) = z+

∞∑k=2

(ν+ (µ+ λ)(k− 1) + β

ν+ β

)zk.

(8)

ϕ(2, 2− α; z) ∗ gµ,νβ,λ(z).sϕ(2, 2− α; z) ∗ gµ,νβ,λ(z) = n-times product.


Similarly, we find the following:

gµβ,λ(z) = z+

∞∑k=2

(β+ (µ+ λ)(k− 1)

β

)zk. (9)

gνβ,λ(z) = z+

∞∑k=2

(ν+ λ(k− 1) + β

ν+ β

)zk. (10)

gνβ(z) = z+

∞∑k=2

(ν+ (k− 1) + β

ν+ β

)zk. (11)

gµλ(z) = z+

∞∑k=2

(1+ (µ+ λ)(k− 1)) zk. (12)

gλ(z) = z+

∞∑k=2

(1+ λ(k− 1)) zk. (13)

Further, a straightforward calculation reveals that many differential operatorsintroduced in other papers are special cases of the differential operator definedby (6) which generalizes some well known differential operators.

1. β = 1, µ = 0, α = 0, we obtain, Aouf et al. differential operator [8].

2. α = 0, we obtain differential operator of Darus and Faisal [29].

3. β = 0, α = 0, we obtain differential operator Darus and Faisal [30].

4. ν = 1, β = o, µ = 0, α = 0, we obtain, Al-Oboudi differential operator[9].

5. ν = 1, β = o, µ = 0, λ = 1, α = 0, we obtain, Salagean’s operator [10].

6. β = l, µ = 0, α = p, we obtain, A. Catas operator [26].

7. ν = 1, β = o, µ = 0, we obtain, Al-Oboudi–Al-Amoudi operator [14, 25].

8. β = 1, λ = 1, µ = 0, α = 0, we obtain, Cho–Srivastava operator [12, 13].

9. ν = 1, β = 1, λ = 1, µ = 0, α = 0, we obtain, Uralegaddi–Somanathaoperator [11].

10. ν = 1, β = o, µ = 0, λ = 0, n = 1, we obtain, Owa–Srivastava operator[7].


11. β = l, µ = 0, α = p, λ = 1, we obtain, Kumar et al. and Srivastava etal. operators [27, 28].

For f ∈ A, we define fm by

fm(z) =1

2m

m−1∑k=0

[ω−kf(ωkz) +ωkf(ωkz)

], (14)

where m be a positive integer and ω = exp(2π/(m)).A function f ∈ A is called λ-starlike with respect to 2m-symmetric conjugate

points and its class is denoted by SVm(λ), if it satisfy the analytic criterion

<

((1− λ)zf ′(z) + λ(zf ′(z)) ′

(1− λ)fm(z) + λzf ′m(z)

)> 0, (z ∈ U, λ ≥ 0),

where fm is given by (14). For details about SVm(λ), we refer to study [15, 16,17, 18].

By using (14), we have

fm(z) =1

2m

m−1∑k=0

ω−kf(ωkz) +ωkf(ωkz)

, implies

In,νλ (α,β, µ)fm(z) =1

2m

m−1∑k=0

ω−kIn,νλ (α,β, µ)f(ωkz)

+ωkIn,νλ (α,β, µ)f(ωkz),

z(In,νλ (α,β, µ)fm(z))′ =

1

2m

m−1∑k=0

ω−kz(In,νλ (α,β, µ)f(ωkz)) ′

+ωkz(Dn,νλ (α,β, µ)f(ωkz)) ′,

In,νλ (α,β, µ)(zf ′m(z)) =1

2m

m−1∑k=0

In,νλ (α,β, µ)(zf ′(ωkz))

+ In,νλ (α,β, µ)(zf ′(ωkz),

In,νλ (α,β, µ)fm(ωjz) = ωjIn,νλ (α,β, µ)fm(z),

In,νλ (α,β, µ)fm(z) = In,νλ (α,β, µ)fm(z).

(15)

Next we introduce new subclasses of analytic functions in U associated withlinear fractional differential operator In,νλ (α,β, µ)f(z), as follow;


Definition 1 For n ∈ N∪0,m ∈ N and α,β, λ, µ, ν ≥ 0, let SVn,νm,λ(α,β, µ)(h)denote the class of functions f defined by (1) and satisfying the analytic cri-terion

z(In,νλ (α,β, µ)f(z)) ′

In,νλ (α,β, µ)fm(z)≺ h(z), z ∈ U,

where h is a convex function in U with h(0) = 1.

Definition 2 Let KVn,νm,λ(α,β, µ)(h) denote the class of functions f defined by

(1) and satisfying the analytic criterion ifIn,νλ (α,β,µ)gm(z)

z 6= 0 and


In,νλ (α,β, µ)gm(z)≺ h(z), z ∈ U,

for some g ∈ SVn,νm,λ(α,β, µ)(h).

Remark 1 In 2010, F. M. Al-oboudi [25], introduced certain subclasses ofanalytic functions which contains only functions of the form given in (13),but there were infinite analytic functions in the open unit disk U, of the formgiven in (8), (9), (10), (11) and (12) respectively, which were out of range ofthe classes given in [25]. Therefore it was necessary to find out or to intro-duce a new differential operator of the form (6). We introduce the subclassesSVn,νm,λ(α,β, µ)(h) and KVn,νm,λ(α,β, µ)(h) of analytic functions by using suchdifferential operator, with a different approach that includes all functions ofthe form given in (8) to (13).

2 Main results

In this section, we have discussed inclusion relations as well as convolutionproperties for the function belonging to the classes SVn,νm,λ(α,β, µ)(h) andKVn,νm,λ(α,β, µ)(h) respectively.

Lemma 1 [19] Let f and g be starlike functions of order 1/2 then so is f ∗ g .

Lemma 2 [20] Let P be a complex function in U with <(P(z)) > 0 for z ∈ Uand let h be a convex function in U. If p is analytic in U with p(0) = h(0)and if

p(z) + P(z)zp ′(z) ≺ h(z),

then p(z) ≺ h(z).


Lemma 3 [21] Let c > −1 and let Ic : A→ A be the integral operator definedby F = Ic(f), where

F(z) =c+ 1

zc

∫ z0

tc−1f(t)dt.

Let h be a convex function, with h(0) = 1 and then <(h(z) + c) > 0, z ∈ U. If

f ∈ A and zf ′(z)f(z) ≺ h(z), then

zF ′(z)

F(z)≺ q(z) ≺ h(z),

where q is univalent and satisfies the differential equation

q(z) +zq ′(z)

q(z) + c= h(z).

Lemma 4 [22] Let f and g, respectively be in the classes K and S, then forevery function F ∈ A, we have

(f(z) ∗ g(z)F(z))(f(z) ∗ g(z))

∈ co(F(U)), z ∈ U,

where co denotes the closed convex hull.

Lemma 5 [22] Let f and g be univalent starlike of order 12 for every function

F ∈ A, we have

(f(z) ∗ g(z)F(z))(f(z) ∗ g(z))

∈ co(F(U)), z ∈ U,

where co denotes the closed convex hull.

Theorem 1 Let h be a convex function in U with h(0) = 1, h(z) = h(z) andlet µ+ λ ≥ ν+ β, if f ∈ SVn,νm,λ(α,β, µ)(h) then

z(In,νλ (α,β, µ)fm(z))′

In,νλ (α,β, µ)fm(z)≺ h(z), z ∈ U. (16)

Moreover, if <(h(z) + ν+β−µ−λ

µ+λ

)> 0 in U then

z(In−1,νλ (α,β, µ((Ωαfm(z))

) ′In−1,νλ (α,β, µ)(Ωαfm(z))

≺ q(z) ≺ h(z), z ∈ U. (17)


Where q is the univalent solution of the differential equation

q(z) +zq ′(z)

h(z) + ν+β−µ−λµ+λ

= h(z), q(0) = 1. (18)

Proof. Because

SVn,νm,λ(α,β, µ)(h) =f ∈ A :


In,νλ (α,β, µ)fm(z)≺ h(z), z ∈ U

.

It is remaining to show that fm ∈ SVn,νm,λ(α,β, µ), since

fm(z) =1

2m

m−1∑k=0

ω−kf(ωkz) +ωkf(ωkz)

.

As

f ∈ SVn,νm,λ(α,β, µ)⇒ z(In,νλ (α,β, µ)f(z)) ′

In,νλ (α,β, µ)fm(z)≺ h(z)

⇒ (Dn,νλ (α,β, µ)zf ′(z))

In,νλ (α,β, µ)fm(z)≺ h(z).

After replacing z by ωjz and ωjz, we get

ω−j (In,νλ (α,β, µ)zf ′(ωjz))

In,νλ (α,β, µ)fm(z)≺ h(z), and ωj

(In,νλ (α,β, µ)zf ′(ωjz))

In,νλ (α,β, µ)fm(z)≺ h(z), (19)

because

h(z) = h(z), In,νλ (α,β, µ)fm(z) = In,νλ (α,β, µ)fm(z), and

In,νλ (α,β, µ)fm(ωjz) = ωjIn,νλ (α,β, µ)fm(z).

Using (19) we have

1

2m

k−1∑k=0

ω−j (In,νλ (α,β, µ)zf ′(ωjz))

In,νλ (α,β, µ)fm(z)+ωj

(In,νλ (α,β, µ)zf ′(ωjz))

In,νλ (α,β, µ)fm(z)≺ h(z),

implies

1

2m

k−1∑k=0

ω−j z(In,νλ (α,β, µ)f(ωjz)) ′


z(In,νλ (α,β, µ)f(ωjz)) ′

In,νλ (α,β, µ)fm(z)≺ h(z),


since we have


=1

2m

m−1∑k=0

ω−kz(In,νλ (α,β, µ)f(ωkz)) ′ +ωkz(In,νλ (α,β, µ)f(ωkz)) ′

and this implies

1

2m

k−1∑k=0

ω−j z(In,νλ (α,β, µ)f(ωjz)) ′


z(In,νλ (α,β, µ)f(ωjz)) ′

In,νλ (α,β, µ)fm(z)

=z(In,νλ (α,β, µ)fm(z))

′

In,νλ (α,β, µ)fm(z),

therefore


In,νλ (α,β, µ)fm(z)≺ h(z).

Hence (16) is satisfied.From (5) we have

In,νλ (α,β, µ)f(z) = Iαλ (In−1,νλ (α,β, µ)f(z)),

implies

In,νλ (α,β, µ)fm(z) =

(ν− µ+ β− λ

ν+ β

)(In−1,νλ (α,β, µ)(Ωαfm(z))

+

(µ+ λ

ν+ β

)z(In−1,νλ (α,β, µ)(Ωαfm(z))

′,

implies

(In−1,νλ (α,β, µ)(Ωαfm(z)) =ν+ β

(µ+ λ)z(µ+λν+β

)−1

∫ z0

t( µ+λν+β

)−1In,νλ (α,β, µ)fm(t)dt.

Applying Lemma 3, we have

f(z) = In,νλ (α,β, µ)fm(z), F(z) = (In−1,νλ (α,β, µ)(Ωαfm(z)),

and

zf ′(z)

f(z)=z(In,νλ (α,β, µ)fm(z))

′

In,νλ (α,β, µ)fm(z)≺ h(z)(proved)


with

<(h(z) +

ν+ β− µ− λ

µ+ λ

)> 0.

Therefore

z(In−1,νλ (α,β, µ((Ωαfm(z))

) ′In−1,νλ (α,β, µ)(Ωαfm(z))

≺ q(z),

and q satisfied the equation

q(z) +zq ′(z)

h(z) + ν+β−µ−λµ+λ

= h(z).

Hence proved.

Corollary 1 Let <(h(z)

)> 0, if f ∈ SVn,νm,λ(α,β, µ)(h) then In,νλ (α,β, µ)fm ∈

S and hence In,νλ (α,β, µ)f is close to convex function.

Theorem 2 Let <(h(z)> 0 and h(z) = h(z) then the following inclusions

hold

SVn+1,νm,λ (α,β, µ)(h) ⊆ SVn,νm,λ(α,β, µ)(h) ⊆ SVn−1,νm,λ (α,β, µ)(h).

Proof. Let f ∈ SVn+1,νm,λ (α,β, µ)(h). To prove SVn+1,νm,λ (α,β, µ)(h) ⊆ SVn,νm,λ(α,β, µ)(h), it is enough to show that f ∈ SVn,νm,λ(α,β, µ)(h).

Applying Theorem 1, if f ∈ SVn+1,νm,λ (α,β, µ)(h) then

z(In+1,νλ (α,β, µ)fm(z))′

In+1,νλ (α,β, µ)fm(z)≺ h(z), z ∈ U,

if Moreover, if <(h(z) + ν+β−µ−λ

µ+λ

)> 0 in U then

z(In,νλ (α,β, µ((Ωαfm(z))

) ′In,νλ (α,β, µ)(Ωαfm(z))

≺ q(z) ≺ h(z), z ∈ U,

and <(q(z) + ν+β−µ−λ

µ+λ

)> 0 in U. Let

p(z) =z(In,νλ (α,β, µ((Ωαf(z))

) ′In,νλ (α,β, µ)(Ωαfm(z))

.


Then p is analytic in U and satisfies

p(z) +zp ′(z)

q(z) + ν+β−µ−λµ+λ

≺ h(z),

by using Lemma 2 p(z) ≺ h(z), implies Ωαf(z) ∈ SVn,νm,λ(α,β, µ)(h), applyingTheorem 4 implies f(z) ∈ SVn,νm,λ(α,β, µ)(h). Hence

SVn+1,νm,λ (α,β, µ)(h) ⊆ SVn,νm,λ(α,β, µ)(h).

Similarly we can show that SVn,νm,λ(α,β, µ)(h) ⊆ SVn−1,νm,λ (α,β, µ)(h), andSVn−1,νm,λ (α,β, µ)(h) ⊆ SVn−2,νm,λ (α,β, µ)(h) and so on, therefore

SVn+1,νm,λ (α,β, µ)(h) ⊆ SVn,νm,λ(α,β, µ)(h) ⊆ SVn−1,νm,λ (α,β, µ)(h).s,

which generalized the Al-Amiri et al. [16] results.

Corollary 2 Taking h(z) = 1+z1−z , in Theorem 2, then

SVn+1,νm,λ (α,β, µ)(1+ z

1− z) ⊆ SVn,νm,λ(α,β, µ)(

1+ z

1− z) ⊆ SVn−1,νm,λ (α,β, µ)(

1+ z

1− z).

Implies that SVn,νm,λ(α,β, µ)( 1+z1−z) are starlike functions with respect to symmet-ric conjugate points.

Theorem 3 If f ∈ SVn,νm,λ(α,β, µ)(h) then f ∗ g ∈ SVn,νm,λ(α,β, µ)(h) where<(h(z)

)> 0 and g is a convex function with real coefficients in U.

Proof. Since f ∈ SVn,νm,λ(α,β, µ)(h), applying Theorem 1, we get In,νλ (α,β, µ)fm(z) ∈ S. Using the convolution properties we have

z(In,νλ (α,β, µ)(f ∗ g)(z)) ′

In,νλ (α,β, µ)(fm ∗ g)(z)=z(In,νλ (α,β, µ)(f(z) ∗ g(z))) ′

In,νλ (α,β, µ)(fm(z) ∗ g(z))

=g(z) ∗ (z(In,νλ (α,β, µ)f(z)) ′

g(z) ∗ In,νλ (α,β, µ)fm(z)

=g(z) ∗ (z(In,νλ (α,β, µ)f(z)) ′/In,νλ (α,β, µ)fm(z))I

n,νλ (α,β, µ)fm(z)

g(z) ∗ In,νλ (α,β, µ)fm(z)

=g(z) ∗ In,νλ (α,β, µ)fm(z)(z(I

n,νλ (α,β, µ)f(z)) ′/In,νλ (α,β, µ)fm(z))

g(z) ∗ In,νλ (α,β, µ)fm(z).


Implies that

z(In,νλ (α,β, µ)(f ∗ g)(z)) ′

In,νλ (α,β, µ)(fm ∗ g)(z)∈ co

(z(In,νλ (α,β, µ)f) ′

In,νλ (α,β, µ)fm(U)

)⊆ h(U), z ∈ U.

Hence

f ∗ g ∈ SVn,νm,λ(α,β, µ)(h).

Theorem 4 If Ωαf(z) ∈ SVn,νm,λ(α,β, µ)(h) then f(z) ∈ SVn,νm,λ(α,β, µ)(h),where <

(h(z)

)> 0, h(z) = h(z).

Proof. Let Ωαf(z) ∈ SVn,νm,λ(α,β, µ)(h), applying Theorem 1, implies

z(In,νλ (α,β, µ)Ωαfm(z))′

In,νλ (α,β, µ)Ωαfm(z)≺ h(z),

or

(In,νλ (α,β, µ)Ωαfm(z) ∈ S.

Because

Ωαf(z) = ϕ(2, 2− α; z) ∗ f(z)

and

In,νλ (α,β, µ)f(z) = [ϕ(2, 2− α; z) ∗ gµ,νβ,λ(z).sϕ(2, 2− α; z) ∗ gµ,νβ,λ(z)]︸︷︷︸ ∗f(z),

therefore we can write that

In,νλ (α,β, µ)fm(z) = ϕ(2− α, 2; z) ∗Dn,νλ (α,β, µ)(Ωαfm(z))

z(In,νλ (α,β, µ)f(z)) ′ = ϕ(2− α, 2; z) ∗ z(In,νλ (α,β, µ)(Ωαf(z)) ′,(20)

where ϕ(2− α, 2; z) ∈ K.Using (20) we have


In,νλ (α,β, µ)fm(z)=ϕ(2− α, 2; z) ∗ z(In,νλ (α,β, µ)(Ωαf(z))) ′

ϕ(2− α, 2; z) ∗ In,νλ (α,β, µ)(Ωαfm(z)),


In,νλ (α,β, µ)fm(z)

=ϕ(2− α, 2; z) ∗ In,νλ (α,β, µ)(Ωαfm(z))

(z(In,νλ (α,β,µ)(Ωαf(z))) ′

In,νλ (α,β,µ)(Ωαfm(z))

ϕ(2− α, 2; z) ∗ In,νλ (α,β, µ)(Ωαfm(z)),


In,νλ (α,β, µ)fm(z)∈ co

(z(In,νλ (α,β, µ)Ωαf) ′

In,νλ (α,β, µ)Ωαfm(U))⊆ h(U), z ∈ U.

(21)


Hence

f(z) ∈ SVn,νm,λ(α,β, µ)(h).

Theorem 5 Let 0 ≤ α1 < α < 1, and Re(h(z)) > 12 , then the following

inclusions hold

SVn,νm,λ(α,β, µ)(h) ⊆ SVn,νm,λ(α1, β, µ)(h) .

Proof. Let f(z) ∈ SVn,νm,λ(α,β, µ)(h), from (7) we have

In,νλ (α,β, µ)f(z) = [ϕ(2, 2− α; z) ∗ gµ,νβ,λ(z).sϕ(2, 2− α; z) ∗ gµ,νβ,λ(z)]︸︷︷︸ ∗f(z),

implies

In,νλ (α1, β, µ)f(z) = [ϕ(2, 2− α1; z) ∗ gµ,νβ,λ(z).sϕ(2, 2− α1; z) ∗ gµ,νβ,λ(z)]︸︷︷︸ ∗f(z),

In,νλ (α1, β, µ)f(z) = [ϕ(2− α, 2− α1; z) ∗ .s ∗ϕ(2− α, 2− α1; z)]︸︷︷︸∗ In,νλ (α,β, µ)f(z),

implies that

z(In,νλ (α1, β, µ)f(z))′ = [ϕ(2− α, 2− α1; z) ∗ .s ∗ϕ(2− α, 2− α1; z)]︸︷︷︸∗ z(In,νλ (α,β, µ)f(z)) ′,

applying same technique, we have

In,νλ (α1, β, µ)fm(z) = [ϕ(2− α, 2− α1; z) ∗ .s ∗ϕ(2− α, 2− α1; z)]︸︷︷︸∗ In,νλ (α,β, µ)fm(z),

since Y. Ling and S. Ding [24] already proved that ϕ(2−α, 2−α1; z) ∈ S(1/2),therefore by Lemma 1 we get [ϕ(2−α, 2−α1; z)∗.s∗ϕ(2−α, 2−α1; z)] ∈ S(1/2).

From last two equations we get

z(In,νλ (α1, β, µ)f(z))′

In,νλ (α1, β, µ)fm(z)=

[ϕ(2 − α, 2 − α1; z) ∗ .s ∗ϕ(2 − α, 2 − α1; z)]︸︷︷︸ ∗z(In,νλ (α, β, µ)f(z)) ′

[ϕ(2 − α, 2 − α1; z) ∗ .s ∗ϕ(2 − α, 2 − α1; z)]︸︷︷︸ ∗In,νλ (α, β, µ)fm(z),


after simplification and using Lemma 5 we deduce that

z(In,νλ (α1, β, µ)f(z))′

In,νλ (α1, β, µ)fm(z)∈ co

(z(In,νλ (α,β, µ)f) ′

In,νλ (α,β, µ)fm(U))⊆ h(U), z ∈ U,

therefore

f ∈ SVn,νm,λ(α1, β, µ)(h).

Hence proved.

Remark 2 1. When ν = 1, µ = β = 0, SVn,1m,λ(α, 0, 0)(h) = SVnm,λ(α)(h),the classes of functions related to starlike functions with respect to sym-metric conjugate points, defined and studied by M. K. Al-Oboudi [25].

2. For n = m = ν = 1, µ = β = 0,and h(z) = 1+z1−z , SV

1,11,λ(α, 0, 0)

(1+z1−z

)=

SVλ,α(1+z1−z

), the class of λ-starlike functions with respect to conjugate

points, defined and studied by Radha [23].

3. For n = m = ν = λ = 1, α = µ = β = 0,and h(z) = 1+z1−z , SV

1,11,1(0, 0, 0)(

1+z1−z

)= SV

(1+z1−z

), the class of starlike functions with respect to conjugate

points, defined and studied by El-Ashwah and Thomas [5].

4. For n = ν = 1, α = µ = β = 0,and h(z) = 1+z1−z , SV

1,1m,λ(0, 0, 0)

(1+z1−z

)=

SVm,λ(1+z1−z

), the class of λ-starlike functions with respect to 2m-symmetric

conjugate points, defined and studied by Al-Amiri et al. [15, 16].

5. For m = ν = 1, n = µ = β = 0, SV0,11,λ(α, 0, 0)(h) = SV(α)(h), the classof functions related to starlike functions with respect to conjugate points,defined and studied by Ravichandran [31].

6. For m = n = ν = 1, α = µ = β = 0 and h(z) = 1+z1−z , SV

1,11,λ(0, 0, 0)

(1+z1−z

)=

SVλ(1+z1−z

), the class of λ-starlike functions with respect to conjugate

points, defined and studied by Radha [23].

7. For λ = n = ν = 1, α = µ = β = 0 and h(z) = 1+z1−z , SV

1,1m,1(0, 0, 0)(h) =

SVm(1+z1−z

), the class of starlike functions with respect to 2m-symmetric

conjugate points, defined by Al-Amiri et al. [16].

8. For ν = 1, µ = β = 0, KVn,1m,λ(α, 0, 0)(h) = KVm,nλ (α)(h), the classes offunctions related to starlike functions with respect to symmetric conju-gate points, defined and studied by M.K. Al-Oboudi [25].


9. For n = ν = 1, α = µ = β = 0 and h(z) = 1+z1−z , KV

1,1m,λ(0, 0, 0)

(1+z1−z

)=

KVmλ(1+z1−z

), the class of λ-close to convex functions with respect to sym-

metric conjugate points, defined and studied by Al-Amiri et al. [16].

10. For m = n = ν = 1, α = µ = β = 0 and h(z) = 1+z1−z , KV

1,11,λ(0, 0, 0)

(1+z1−z

)=

KVλ(1+z1−z

), the class of λ-close to convex functions with respect to sym-

metric conjugate points, defined and studied by Radha [23].

Acknowledgments

The work presented here was fully supported by UKM-AP-2013-09.

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Received: March 21, 2016

Study on subclasses of analytic functionsActa Univ. Sapientiae, Mathematica, 9, 1 (2017) 122{139...

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