some generalized special functions and their properties

21
(s, k) s, k > 0 (s, k) (s, k)

Upload: others

Post on 30-Jun-2022

2 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Some Generalized Special Functions and their Properties

Advances in the Theory of Nonlinear Analysis and its Applications 1 (2022) No. 1, 45�65.https://doi.org/10.31197/atnaa.768532Available online at www.atnaa.org

Research Article

Some Generalized Special Functions and their

Properties

Shahid Mubeena, Syed Ali Haider Shaha, Gauhar Rahmanb, Kottakkaran Sooppy Nisarc, Thabet Abdeljawadd

aDepartment of Mathematics, University of Sargodha, Sargodha, Pakistan.bDepartment of Mathematics, Shaheed Benazir Bhutto University, Sheringal, Upper Dir, Pakistan.cDepartment of Mathematics, College of Arts and Sciences, Prince Sattam bin Abdulaziz University, Wadi Aldawaser, Saudi Arabia.dDepartment of Mathematics, Department of Mathematics and General Sciences, Prince Sultan University, Riyadh, Saudi Arabia.

Abstract

In the present paper, �rst, we investigate a generalized Pochhammer's symbol and its various properties interms of a new symbol (s, k), where s, k > 0. Then, we de�ne a generalization of gamma and beta functionsand their various associated properties in the form of (s, k). Also, we de�ne new generalization of hyperge-ometric functions and develop di�erential equations for generalized hypergeometric functions in the form of(s, k). We present that generalized hypergeometric functions are the solution of the said di�erential equa-tion. Furthermore, some useful results, properties and integral representation related to these generalizedPochhammer's symbol, gamma function, beta function, and hypergeometric functions are presented.

Keywords: Pochhammer symbol beta function Gamma function generalized Pochhammer symbolgeneralized hypergeometric function.2010 MSC: 33C20, 33C05, 33C10; 26A09.

1. Introduction

The theory of special functions comprises a major part of mathematics. In last three centuries, theessential of solving the problems take place in the �elds of classical mechanics, hydrodynamics and control

Email addresses: [email protected] (Shahid Mubeen), [email protected] (Syed Ali Haider Shah),[email protected] (Gauhar Rahman), [email protected], [email protected] (Kottakkaran Sooppy Nisar),[email protected] (Thabet Abdeljawad)

Received July 14, 2020, Accepted October 09, 2021, Online October 16, 2021

Page 2: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 46

theory, motivated the development of the theory of special functions. This �eld also has wide applicationsin both pure mathematics and applied mathematics. Numerous extensions of special functions have beenintroduced by many authors (see [1, 2, 3, 4]).

Agarwal et al. [5] proved new di�erential equations for the extended Mittag-Le�er function by usingSaigo-Maeda fractional di�erential operators. Mdallal et al. [6] also worked on the di�erential equationsof fractional order with variables coe�cients. They found the eigenvalues by applying associated boundaryconditions. Also, they present the eigenfunctions in the form of Mittag-Le�er functions. Babakhani et al.

[7] used thye �xed point theorems to �nd the existence of positive solutions for a non-autonomous fractionaldi�erential equation with integral boundary conditions. They also presented some examples related todi�erential equations. Jarad et al. [8] investigated the modi�ed Laplace transform and related properties.They used these results to �nd the solution of some ordinary di�erential equations of a certain type generalizedfractional derivatives.

Diaz et al. [9, 10, 11] have introduced gamma and beta k-functions and proved a number of theirproperties. They have also studied zeta k-functions and hypergeometric k-functions based on Pochhammerk-symbols for factorial functions. In [12, 13, 14, 15], the researchers studied the generalized gamma k-function and proposed its various properties. Later on, Mubeen and Habibullah [32] proposed the so-calledk-fractional integral based on gamma k-function and its applications. In [33], Mubeen and Habibullahde�ned the integral representation of generalized con�uent hypergeometric k-functions and hypergeometrick-functions by utilizing the properties of Pochhammer k-symbols, k-gamma, and k-beta functions. In [34],Mubeen et al. proposed the following second order linear di�erential equation for hypergergeometric k-functions as

kω(1− kx)ω′′ + [γ − (α+ β + k) kx]ω′ − αβω = 0.

The solution in the form of the so-called k-hypergeometric series of k-hypergeometric di�erential equation byutilizing the Frobenius method can be found in the work of Mubeen et al. [35, 36]. Recently, Li and Dong[37] investigated the hypergeometric series solutions for the second order non-homogeneous k-hypergeometricdi�erential equation with the polynomial term. Rahman et al. [38, 39] proposed the generalization of Wrighttype hypergeometric k-functions and derived its various basic properties.

Qi and Wang [40] worked on Young's integral Inequalities and discussed its geometric interpretation. Ad-jimi and Benbachir [41] worked on Katugampola fractional di�erential equation with Erdelyi-Kober integralboundary conditions. Furthermore, Mubeen and Iqbal [16] investigated the generalized version of Grüss-typeinequalities by considering k-fractional integrals. Agarwal et al. [18] established certain Hermite-Hadamardtype inequalities involving k-fractional integrals. Set et al. [27] proposed generalized Hermiteâ��Hadamardtype inequalities for Riemannâ��Liouville k-fractional integral. Östrowski type k-fractional integral inequali-ties can be found in the work of Mubeen et al. [17]. Many researchers have established further the generalizedversions of Riemann-Liouville k-fractional integrals, and de�ned a large number of various inequalities byusing di�erent kind of generalized fractional integrals. The interesting readers may consult [19, 31, 25, 20].The Hadamard k-fractional integrals can be found in the work of Farid et al. [21]. In [23] Farid proposedthe idea of Hadamard-type inequalities for k-fractional Riemann-Liouville integrals. In [24, 22], the authorshave introduced the inequalities by employing Hadamard-type inequalities for k-fractional integrals. Nisaret al. [28] investigated Gronwall type inequalities by utilizing Riemann-Liouville k-fractional derivatives andHadamard k-fractional derivatives [28]. In [28], they presented dependence solutions of certain k-fractionaldi�erential equations of arbitrary real order with initial conditions. Samraiz et al. [26] proposed Hadamardk-fractional derivative and related properties. Recently, Rahman et al. [29] de�ned generalized k-fractionalderivative operator. Jangid et al. [30] worked on the generalization of integral inequalities. By using theSaigo k-fractional integral operators, they found some new inequalities for the Chebyshev functional for twosynchronous functions.

Page 3: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 47

By getting motivation from Diaz and other researchers working on the generalization and extensions ofthe special functions, we get the idea to obtain the more generalized and extended form of special functions.The structure of the paper is organized as follows:In Section 2, we study the generalized Pochhammer's symbol, gamma function and beta function in termsof (s, k). Also, some basic properties are presented. In Section 3, generalized hypergeometric functions,di�erential equation for hypergeometric function and their associated properties are discussed. In Section 4,concluding remarks are given.

2. Main Results

In this section, we introduce generalized Pochhammer's symbol and its various associated properties.Also, generalization of gamma and beta functions and their associated properties are presented.

De�nition 2.1. The generalized Pochhammer's symbol in term of (s, k) is de�ned as

s(α)kn = α(α+ (s/k)) · · · (α+ ((n− 1)s/k)), α ∈ C,s, k ∈ R+, n ∈ N, s > k > 0. (1)

s(b)knm = 2mn s( bm)kns( bk+s

mk )kn · · · s(bk+(m−1)s

mk )kn

Just as for the usual Γ, the function sΓk admits an in�nite product expression given by

1sΓk(z)

= z(s/k)−(kz)/se(kzγ)/s∞∏n=1

[(1 +

kz

ns

)exp

(− kz

ns

)], (2)

where γ is Euler-Mascheroni constant, de�ned by

γ = limn→∞

(Hn − log(n)) ≈ 0.57721566490,

where Hn =n∑

m=1

1m .

Lemma 2.2. For all z, the Euler product is given as

sΓk(z) =1

z(s/k)−kzs

∞∏n=1

[(n+ 1

n

) kzs(

1 +kz

sn

)−1]. (3)

Proof. Using equation (2), we have

1sΓk(z)

= z(s/k)−−kzs e

kγzs

∞∏n=1

[(1 +

kz

ns

)exp

(−kzns

)].

z(s/k)−kzssΓk(z) = e−

kγzs lim

n→∞

n∏m=1

[(1 +

kz

sm

)−1

exp

(kz

sm

)]. (4)

Sinceγ = lim

n→∞

[Hn − log(n+ 1)

]. (5)

Therefore equation (5) becomes

γ = limn→∞

[Hn −

n∑m=1

log

(m+ 1

m

)]. (6)

Page 4: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 48

Multiply the whole equation (6) by −kzs , we obtain

−kzγs

= limn→∞

[− kz

sHn +

n∑m=1

log

(m+ 1

m

) kzs].

By taking exponential, we get

e−kzγs = lim

n→∞

[exp

(− kz

sHn

)exp

n∑m=1

log

(m+ 1

m

) kzs]. (7)

Since Hn =n∑

m=1

1m , put in equation (7), we have

e−kzγs = lim

n→∞

[exp

(− kz

s

n∑m=1

1

m

)exp

n∑m=1

log

(m+ 1

m

) kzs]

= limn→∞

[exp

( n∑m=1

−kzsm

)exp

n∑m=1

log

(m+ 1

m

) kzs].

And so

e−kzγs = lim

n→∞exp

( n∑m=1

log

(exp

(−kzsm

)))(exp

n∑m=1

log(m+ 1

m

) kzs

)

e−kzγs = lim

n→∞

n∏m=1

exp

(−kzsm

)(m+ 1

m

) kzs

. (8)

This implies that

sΓk(z) =1

z(s/k)−kzs

∞∏n=1

[(n+ 1

n

) kzs(1 +

kz

sn

)−1].

Lemma 2.3. For all �nite z, the di�erence equation is given below

sΓk(z + (s/k)) = z sΓk(z). (9)

Proof. Using equation (3), we have

sΓk(z + (s/k))sΓk(z)

=

1

(z+(s/k))(s/k)−k(z+(s/k))

s

∞∏n=1

[(n+1n )

k(z+(s/k))s (1 + kz+k

sn )−1]

1

z(s/k)−kzs

∞∏n=1

[(n+1n )

kzs (1 + kz

ns)−1]

=z(s/k)

z + (s/k)limn→∞

n∏m=1

(m+ 1

m)(

sm+ kz

sm+ kz + k)

=z(s/k)

z + (s/k)limn→∞

[(n+ 1

1)(

s+ zk

sn+ kz + k)

]= z.

ThereforesΓk(z + (s/k)) = z sΓk(z).

Page 5: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 49

De�nition 2.4. The Gamma (s, k)-function is de�ned as

sΓk(z) = limn→∞

n!sn(nsk )kzs

kn s(z)kn, z ∈ C− kZ, (10)

s, k ∈ R+, s > k > 0, <(z) > 0. (11)

Lemma 2.5. For z ∈ C, <(z) > 0, we have

sΓk(z) =

∞∫0

tz−1e−kts/k

s dt.

Proof. By equation (10), we have

sΓk(z) =

∞∫0

tz−1e−kts/k

s dt

= limn→∞

(nsk

)ks∫

0

tz−1

(1− kt

sk

ns

)dt.

Let An,i(z), i = 0, · · · , n, be given by

An,i(z) =

(nsk

)ks∫

0

tz−1

(1− kt

sk

ns

)dt.

The following recursive formula is proven using integration by parts

An,i(z) =i

nzAn,i(z +

s

k).

Also,

An,0(z) =

(nsk

)ks∫

0

tz−1dt =(nsk )

kzs

z.

Therefore,

An,n(z) =n!sn(nsk )

kzs

kn s(z)kn(1 + zkns)

and

sΓk(z) = limn→∞

An,n(z) = limn→∞

n!sn(nsk )kzs

kn s(z)kn.

sΓk(z) =

∞∫0

tz−1e−kts/k

s dt, z ∈ C, s, k ∈ R+, s > k > 0, <(z) > 0. (12)

Page 6: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 50

Lemma 2.6. If α is neither zero nor a negative integer, then

s(α)kn =sΓk(α+ ns

k

)sΓk(α)

. (13)

Proof. ConsidersΓk(α+

ns

k

)=s Γk

(α+

(n− 1 + 1)s

k

).

Using equation (9), for n a positive integer, we have

sΓk(α+

ns

k

)=

(α+

ns− sk

)sΓk(α+

ns− sk

)=

(α+

ns− sk

)(α+

ns− 2s

k

)· · ·α sΓk(α)

i.e.,sΓk(α+

ns

k

)= α

(α+

s

k

)· · ·(α+

ns− 2s

k

)(α+

ns− sk

)sΓk(α).

Since

s(α)kn = α

(α+

s

k

)· · ·(α+

ns− 2s

k

)(α+

ns− sk

),

therefore we havesΓk(α+

ns

k

)= s(α)kn

sΓk(α).

This implies that

s(α)kn =sΓk(α+ ns

k

)sΓk(α)

.

De�nition 2.7. The beta (s, k)-function is de�ned as

sβk(x, y) =k

s

1∫0

tkxs−1(1− t)

kys−1dt, s, k ∈ R+, s > k > 0, <(x) > 0, <(y) > 0. (14)

The beta (s, k)-function can be de�ned in terms of algebraic functions by putting t = sin2 Φ, given as

sβk(x, y) =2k

s

π2∫

0

sin2kxs−1 Φ cos

2kys−1 ΦdΦ, <(x) > 0, <(y) > 0. (15)

Lemma 2.8. If Re(p) > 0 and Re(q) > 0, then

sβk(p, q) =sΓk(p) sΓk(q)sΓk(p+ q)

. (16)

Proof. Using equation (12), We have

sΓk(p) sΓk(q) =

∞∫0

e−ku

sks u

kps−1du

∞∫0

e−kvsks v

kqs−1dv. (17)

Page 7: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 51

In equation (17), use u = x2 and v = y2. Thus du = 2xdx and dv = 2ydy.Now if u→ 0, then x→ 0. If v → 0, then y → 0. If u→∞, then x→∞. If v →∞, then y →∞. We have

sΓk(p) sΓk(q) =

∞∫0

e−kx

2sks x

2kps−22xdx

∞∫0

e−ky

2sks y

2kqs−22ydy

= 4

∞∫0

∞∫0

e−( kx2sks

+ ky2sks

)x2kps−1y

2kqs−1dxdy. (18)

Let x = r cos θ, y = r sin θ and r2 = x2 + y2, where 0 < r < ∞ and 0 < θ < π2 , and dxdy = rdrdθ. Put in

the equation (18), we have

sΓk(p) sΓk(q) = 4

∞∫0

π2∫

0

e−kr

2sks r2p−1 cos2 kp

s−1 θr2q−1 sin

2kqs−1 θrdrdθ

= 2

∞∫0

e−kr

2sks r2p+2q−22rdr

π2∫

0

cos2pks−1 θ sin

2kqs−1 θdθ. (19)

Put the following in equation (19)

r2 = t θ =π

2− φ

2rdr = dt dθ = −dφ,

as r → 0, t→ 0 and as r →∞, t→∞. Also if θ = 0, then φ = π2 and if θ = π

2 , then φ = 0, so we have

sΓk(p) sΓk(q) =

∞∫0

e−ktsks tp+q−1dt 2

π2∫

0

sin2kps−1 φ cos

2kqs−1 φdφ

= sΓk(p+ q) sβk(p, q).

By using equation (12) and equation (15) we have

sβk(p, q) =sΓk(p) sΓk(q)sΓk(p+ q)

.

Lemma 2.9. Prove that

(1− sy

k)−

kas =

∞∑n=0

s(a)kn yn

n!. (20)

Proof. The binomial theorem states that

(1− sy

k)−

kas =

∞∑n=0

(−kas )(−ka

s − 1)(−kas − 2)...(−ka

s − n+ 1)(−1)n( syk )n

n!,

which may be written as

(1− sy

k)−

kas =

∞∑n=0

(a)(a+ sk )(a+ 2 sk )...(a+ (n− 1) sk ) yn

n!.

Page 8: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 52

Therefore, in factorial function notation,

(1− sy

k)−

kas =

∞∑n=0

s(a)kn yn

n!.

2.1. Some important results of Pochhammer (s, k)-symbol.

In this section, some important results of Pochhammer's (s, k)-symbol are presented.

sΓk( s−nsk − α)sΓk( sk − α)

=sΓk( s−nsk − α)

( s−sk − α)( s−2sk − α) · · · ( s−nsk − α) sΓk( s−nsk − α)

=(−1)n

α(α+ sk ) · · · (α+ (n− 1) sk )

=(−1)n

s(α)kn.

Thus,

sΓk( s−nsk − α)sΓk( sk − α)

=(−1)n

s(α)kn.

s(α)kms(α+

ms

k)kn = α(α+

s

k) · · · (α+

(m− 1)s

k)(α+

ms

k)(α+

(m+ 1)s

k) · · ·

(α+ms+ (n− 1)s

k) =s (α)kn+m.

Thus,

s(α)kms(α+

ms

k)kn =s (α)kn+m.

(−1)m s(α)kns( s−nsk − α)km

=(−1)mα(α+ s

k ) · · · (α+ (n−1)sk )

( s−nsk − α)(2s−nsk − α) · · · ( s−nk+(m−1)s

k − α)

= α(α+s

k) · · · (α+

(n−m− 1)s

k) =s (α)kn−m.

Thus,

(−1)m s(α)kns( s−nsk − α)km

=s (α)kn−m.

Example 2.10. Prove that

(n−m)! =(−s)mn!

km s(−nsk )km

.

Page 9: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 53

Proof.

s(α)kn−m =(−1)m s(α)kns( s−nsk − α)km

,

taking α = sk , we have

s(s

k)kn−m =

(−1)m s( sk )kns(−nsk )km

,

(s

k)n−m(n−m)! =

(−1)m ( sk )nn!s(−nsk )km

,

(n−m)! =(−s)mn!

km s(−nsk )km

.

2.1.1. Legender's (s, k)-Duplication formula.

Lemma 2.11. Prove that √kπ

ssΓk(2z) = 2

2kzs−1 sΓk(z) kΓk(z +

s

2k).

Proof. Since s(α)k2n = 22n s(α2 )kns(kα+s

2k )kn and α = 2z, we have

s(2z)k2n = 22n s(2z

2)kn

s(2kz + s

2k)kn

sΓk(2z + 2nsk )

sΓk(2z)=

22n sΓk(2z2 + ns

k ) sΓk(2kz+s+2ns2k )

sΓk(2z2 ) sΓk(2kz+s

2k ).

Using

sΓk(z) = limn→∞

n!sn(nsk )kzk

kn s(z)kn

and

1 = limn→∞

n!sn(nsk )kzk

kn sΓk(z + nsk ).

sΓk(2z)sΓk(z) sΓk(z + s

2k )= lim

n→∞

sΓk(2z + 2nsk )n!k2n sn(nsk )

kzs

(2n)!s2nkn(2nsk )

2kzs sΓk(z + ns

k )

×n!sn(nsk )

kzs (2n)!s2n(2ns

k )2kzs k2n

(nsk )4kz−3s

s k2nknn!n!22n sΓk(z + s+2ns2k )

=

√s

klimn→∞

(2n)!√n

22n(n!)2=

√s

kC.

Page 10: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 54

Put z = s2k in above equation and use sΓk( s

2k ) =√

kπs . This implies that

C =

√1

π.

Therefore √kπ

ssΓk(2z) = 2

2kzs−1 sΓk(z) kΓk(z +

s

2k).

De�nition 2.12. The binomial (s, k)-theorem states that

(1 + sz/k)n =

(n

0

)(sz/k)0 +

(n

1

)(sz/k)1 + · · ·

(n

n

)(sz/k)n + · · · , (21)

i.e.

(1 + sz/k)n =∞∑m=0

(n

m

)(sz/k)m (22)

and

(1 + sz/k)n = 1 + (nsz/k) +n(n− 1)(sz/k)2

2!+ · · · . (23)

Also

(1− sz/k)−kαs =

∞∑n=0

s(α)knzn

n!, α ∈ R, s > k > 0. (24)

3. Generalized hypergeometric functions and their properties

In this section, a new generalization of hypergeometric functions are introduced with the help of newgeneralized Pochhammer's symbol (1). We also introduce the generalized hypergeometric di�erential equa-tions and derive that the new generalized hypergeometric function is the solutions of the said di�erentialequations. Certain basic properties are also presented.

Theorem 3.1. Prove that sz(k − sz)ω′′ + [k2c− (ak + bk + s)sz]ω′ − abk2ω = 0

if and only if s2F

k1

((a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z) =∞∑n=0

s(a)kns(b)knz

n

s(c)knn!is a solution.

Proof. Let ω = s2F

k1

((a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z) be a solution of the di�erential equation. Now Consider θ = z ddz

ω =

∞∑n=0

s(a)kns(b)knz

n

s(c)knn!. (25)

s

(s

kθ + c− s

k

)ω =

s

(s

kθ + c− s

k

) ∞∑n=0

s(a)kns(b)knz

n

s(c)kn n!

=sz

(a+

k

)(b+

k

)ω.

Thuss

(s

kθ + c− s

k

)ω − sz

(a+

k

)(b+

k

)ω = 0, (26)

Page 11: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 55

after a little simpli�cation, we get

sz(k − sz)ω′′ + [k2c− (ak + bk + s)sz]ω′ − abk2ω = 0.

Conversely:Let sz(k − sz)ω′′ + [k2c− (ak + bk + s)sz]ω′ − abk2ω = 0, suppose that

ω =∞∑n=0

dnzn

ω′ =

∞∑n=1

ndnzn−1

ω′′ =∞∑n=2

n(n− 1)dnzn−2,

put these values in di�erential equation

sz(k − sz)∞∑n=2

n(n− 2)dnzn−1 + [k2c− (ak + bk + s)sz]

∞∑n=1

ndnzn−1 − abk2

∞∑n=0

dnzn = 0,

therefore

sk

∞∑n=2

n(n− 1)dnzn−1 − s

∞∑n=2

n(n− 1)dnzn + k2c

∞∑n=1

ndnzn−1

− [abk2 + (ak + bk + s)s]∞∑n=0

dnzn = 0

replace n by (n+ 1)

sk

∞∑n=1

n(n+ 1)dn+1zn − s

∞∑n=2

n(n− 1)dnzn + k2c

∞∑n=0

(n+ 1)dn+1zn

− [abk2 + (ak + bk + s)s]∞∑n=0

dnzn = 0.

comparing the coe�cient of zn on both sides

skn(n+ 1)dn+1 − sn(n− 1)dn + k2c(n+ 1)dn+1 − [abk2 + (ak + bk + s)s]dn = 0.

Therefore

dn+1 =sn(n− 1) + [abk2 + (ak + bk + s)s]

skn(n+ 1) + k2c(n+ 1)dn

=(a+ (ns/k))(b+ (ns/k))

(n+ 1)(c+ (sn/k))dn.

This implies

dn =s(a)kn

s(b)kns(c)knn!

ω =

∞∑n=0

s(a)kns(b)knz

n

s(c)knn!

ω = s2F

k1

((a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z)

Page 12: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 56

s2F

k1

((a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z) =∞∑n=0

s(a)kns(b)knz

n

s(c)knn!.

De�nition 3.2. The hypergeometric (s, k)-function is de�ned as

s2F

k1

((a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z) =∞∑n=0

s(a)kns(b)knz

n

s(c)knn!, (27)

provided a, b, c ∈ C, s > k > 0, |z| < ks and <(c− b− a) > 0.

Theorem 3.3. If <(c) > <(b) > 0, s > k > 0, then for all �nite z < ks

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z]

=k sΓk(c)

s sΓk(b) sΓk(c− b)

1∫0

tkbs−1(1− t)

kc−kbs−1

(1− sxt

k

)− kas

dt.

Proof.

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z] =∞∑n=0

s(a)kns(b)kn zn

s(c)kn n!

=∞∑n=0

s(a)kns(b)kn z

n

s(c)knn!,

by using s(a)kn =sΓk(a+(ns)/k)

sΓk(a), we have

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z]=∞∑n=0

s(a)knsΓk(b+ (ns)/k) sΓk(c) zn

sΓk(c+ (ns)/k) sΓk(b) n!

=sΓk(c)

sΓk(b) sΓk(c− b)

∞∑n=0

s(a)knsΓk(b+ (ns)/k) sΓk(c− b) zn

sΓk(c+ (ns)/k) n!

=k sΓk(c)

s sΓk(b) sΓk(c− b)

1∫0

tkbs−1(1− t)

kc−kbs−1

(1− szt

k

)− kas

dt.

Theorem 3.4. If <(c− b− a) > 0, s > k > 0, then

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣ks]

=sΓk(c) sΓk(c− b− a)sΓk(c− b) sΓk(c− a)

.

Page 13: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 57

Proof. Let |z| < ks and consider

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣ks]

=k sΓk(c)

s sΓk(b) sΓk(c− b)

1∫0

tkbs−1(1− t)

kc−kbs−1(1− t

)− kas dt

=sΓk(c) sΓk(c− b− a)sΓk(c− b) sΓk(c− a)

.

Theorem 3.5. If |z| < ks and |z|

|(1−(s/k)z)| < 1, s > k > 0, then

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)z

]= (1− (s/k)z)−

kass2F

k1

[(a; s, k), (c− b; s, k)

(c; s, k)

−kzk − sz

].

Proof. Let |z| < ks and consider

(1− (s/k)z)−kass2F

k1

[(a; s, k), (c− b; s, k)

(c; s, k)

−kzk − sz

]=

∞∑m=0

s(a)kms(c− b)km zm(1− (s/k)z)−

kas−m

s(c)km m!

=∞∑n=0

s(a)kns(b)kn z

n

s(c)kn n!

= s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)z

].

Theorem 3.6. If |z| < ks , s > k > 0, then

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z] = (1− (s/k)z)−kc−ka−kb

ss2F

k1

[(c− a; s, k), (c− b; s, k)

(c; s, k)

∣∣∣∣z] .Proof. Let |z| < k

s and consider

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z] = (1− (s/k)z)−kass2F

k1

[(a; s, k), (c− b; s, k)

(c; s, k)

∣∣∣∣ −kzk − sz

].

Suppose that y = −kzk−sz , we have

(1− (s/k)z)kass2F

k1

[(a; s, k), (b; s, k)

(c; s, k)z

]= s

2Fk1

[(a; s, k), (c− b; s, k)

(c; s, k)

∣∣∣∣y]= (1− (s/k)y)

kb−kcs

s2F

k1

[(c− b; s, k), (c− a; s, k)

(c; s, k)

∣∣∣∣ −kyk − sy

].

This implies that

s2F

k1

[(a; s, k), (b; s, k)

(c; s, k)z

]= (1− (s/k)z)−

kc−ka−kbs

s2F

k1

[(c− a; s, k), (c− b; s, k)

(c; s, k)

∣∣∣∣z] .

Page 14: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 58

Lemma 3.7. Show that

s2F

k1

[(−nsk ; s, k), ( sk − b−

nsk ; s, k)

(a; s, k)

∣∣∣∣ks]

=s(a+ b− s

k )kns(a)kn

s(a+ b− sk )kn

.

Proof. Since Gauss summation (s, k)-theorem

s2F

k1

[(−nsk ; s, k), ( sk − b−

nsk ; s, k)

(a; s, k)

∣∣∣∣ks]

=sΓk(a) sΓk(a+ b+ 2ns−s

k )sΓk(a+ sn

k ) sΓk(a+ b+ ns−sk )

=s(a+ b− s

k )k

s(a)k s(a+ b− sk )k

.

Theorem 3.8. If 2b is neither zero nor a negative integer and if |sy| < k2 and

∣∣ syk−sy

∣∣ < 1, s > k > 0, then

kkas (k − sy)−

kass2F

k1

[(a2 ; s, k), (ka+s

2k ; s, k)( s

2k + b; s, k)

∣∣∣∣ sky2

(k − sy)2

]= s

2Fk1

[(a; s, k), (b; s, k)

(2b; s, k)

∣∣∣∣2y] .Proof. Let |sy| < k

2 and∣∣ syk−sy

∣∣ < 1, we have

kkas (k − sy)−

kass2F

k1

[(a2 ; s, k), (ka+s

2k ; s, k)( s

2k + b; s, k)

∣∣∣∣ sky2

(k − sy)2

]=

∞∑n=0

∞∑m=0

s(a2 )kms(ka+s

2k )kms(a+ 2ms

k )kn yn+2msm

km s(b+ s2k )km n!m!

= s2F

k1

[(a; s, k), (b; s, k)

(2b; s, k)

∣∣∣∣2y] .

De�nition 3.9. Con�uent hypergeometric (s, k)-function is a solution of con�uent hypergeometric

di�erential (s, k)-equation which is a degenerate form of a hypergeometric di�erential (s, k)-equation where

two regular singularities out of three merge into an irregular singularity.

We de�ne the con�uent hypergeometric (s, k)-function as

s1F

k1

((a; s, k)(c; s, k)

∣∣∣∣z) =

∞∑n=0

s(a)kn zn

s(c)kn n!, (28)

for |z| <∞, c 6= 0,−s/k,−2s/k, · · · .

Theorem 3.10. If <(b) > <(a) > 0, s > k > 0, then for all �nite z

s1F

k1

[(a; s, k)(b; s, k)

∣∣∣∣z]

=k sΓk(b)

s sΓk(a) sΓk(b− a)

1∫0

tkas−1(1− t)

kb−kas−1extdt.

Page 15: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 59

Proof.

s1F

k1

[(a; s, k)(b; s, k)

∣∣∣∣z] =∞∑n=0

s(a)kn zn

s(b)kn n!.

By using s(a)kn =sΓk(a+(ns)/k)

sΓk(a), we have

s1F

k1

[(a; s, k)(b; s, k)

∣∣∣∣z]

=k sΓk(b)

s sΓk(a) sΓk(b− a)

1∫0

tkas−1(1− t)

kb−kas−1eztdt.

De�nition 3.11. The Generalized hypergeometric (s, k)-functions is de�ned as

srF

kq

[(α1; s, k), (α2; s, k), · · · , (αr; s, k)(β1; s, k), (β2; s, k), · · · , (βq; s, k)

∣∣∣∣z] =∞∑n=0

s(α1)kns(α2)ki · · · s(αr)kn zn

s(β1)kns(β2)kn · · · s(βq)knn!

, (29)

for all αi, βj ∈ C, βj 6= 0,−s/k,−2s/k, · · · , |z| < ks where i = 1, 2, · · · , r and j = 1, 2, · · · , q.

It is known that

(i) if r ≤ q, the series converges for all �nite z,(ii) if r = q + 1, the series converges for |z| < k

s and diverges for |z| > ks ,

(iii) if r > q + 1, the series diverges for z 6= 0 unless the series terminates.

Theorem 3.12. If r ≤ s+ 1, if <(b1) > <(a1) > 0, if no one of b1, b2, · · · bs is zero or a negative integer,

s > k > 0 and if |z|ks , then

srF

kq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣z] =k sΓk(b1)

s sΓk(a1)sΓk(b1 − a1)

×1∫

0

tka1s−1(1− t)

kb1−ka1s

−1 sr−1F

kq−1

[(a2; s, k), · · · , (ar; s, k)(b2; s, k), · · · , (bq; s, k)

∣∣∣∣zt] dt.Proof.

srF

kq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣z]=

∞∑n=0

s(a1)kns(a2)kn · · ·s (ar)

kn z

n

s(b1)kns(b2)kn · · ·s (bq)kn n!

=k sΓk(b1)

s sΓk(a1)sΓk(b1 − a1)

×1∫

0

tka1s−1(1− t)

kb1−ka1s

−1 sr−1F

kq−1

[(a2; s, k), · · · , (ar; s, k)(b2; s, k), · · · , (bq; s, k)

∣∣∣∣zt] dt.

Page 16: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 60

Theorem 3.13. If <(α) > 0, <(β) > 0 and if m and p are positive integers, s > k > 0, then inside the

region of convergence of the resultant series

t∫0

xkαs−1(t− x)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cxm(t− x)p]dx

=s

ksBk(α, β)t

kα+kβs−1

× sr+m+p F

kq+m+p

(a1; s, k), (a2; s, k), · · · , (ar; s, k), ( αm ; s, k), (kα+s

mk ; s, k),

· · · , (kα+(m−1)smk ; s, k), (kβ+s

pk ; s, k), · · · , (kβ+(p−1)spk ; s, k)

(b1; s, k), (b2; s, k), · · · , (bq; s, k),

( α+β(m+p) ; s, k), (kα+kβ+s

(m+p)k ; s, k), · · · , (kα+kβ+(m+p−1)s(m+p)k ; s, k)

∣∣∣∣mmppctm+p

m+ pm+p

.Proof. Let <(α) > 0, <(β) > 0 and if m and p are positive integers and consider

t∫0

xkαs−1(t− x)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cxm(t− x)p]dx.

Suppose that x = tv ⇒ dxdv = t when x = 0 ⇒ v = 0 when x = t ⇒ v = 1, we have

t∫0

xkαs−1(t− x)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cxm(t− x)p]dx

=

1∫0

(tv)kαs−1(t− tv)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cvmtm+p(1− v)p]tdv

=s

ksBk(α, β)t

kα+kβs−1

× sr+m+pF

kq+m+p

(a1; s, k), (a2; s, k), · · · , (ar; s, k), ( αm ; s, k), (kα+s

mk ; s, k),

· · · , (kα+(m−1)smk ; s, k), (kβ+s

pk ; s, k), · · · , (kβ+(p−1)spk ; s, k)

(b1; s, k), (b2; s, k), · · · , (bq; s, k),

( α+β(m+p) ; s, k), (kα+kβ+s

(m+p)k ; s, k), · · · , (kα+kβ+(m+p−1)s(m+p)k ; s, k)

∣∣∣∣mmppctm+p

m+ pm+p

.

Theorem 3.14. If <(α) > 0, <(β) > 0 and if m is a positive integers, s > k > 0, then inside the region of

convergence of the resultant series

t∫0

xkαs−1(t− x)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cxm] dx=s

ksBk(α, β)t

kα+kβs−1

× sr+mF

kq+m

(a1; s, k), (a2; s, k), · · · , (ar; s, k),

( αm ; s, k), (kα+smk ; s, k), · · · , (kα+(m−1)s

mk ; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k),

(α+βm ; s, k), (kα+kβ+s

mk ; s, k), · · · , (kα+kβ+(m−1)smk ; s, k)

∣∣∣∣ctm .

Proof. Let <(α) > 0, <(β) > 0 and if m is a positive integers and considert∫

0

xkαs−1(t− x)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cxm] dx.

Page 17: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 61

Suppose that x = tv ⇒ dxdv = t when x = 0 ⇒ v = 0 when x = t ⇒ v = 1, we have

t∫0

xkαs−1(t− x)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cxm] dx=

1∫0

(tv)kαs−1(t− tv)

kβs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣cvmtm] tdv=s

ksBk(α, β)t

kα+kβs−1

× sr+mF

kq+m

(a1; s, k), (a2; s, k), · · · , (ar; s, k),

( αm ; s, k), (kα+smk ; s, k), · · · , (kα+(m−1)s

mk ; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k),

(α+βm ; s, k), (kα+kβ+s

mk ; s, k), · · · , (kα+kβ+(m−1)smk ; s, k)

∣∣∣∣ctm .

Lemma 3.15. Show that

d

dzsrF

kq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣z] =

r∏m=1

am

q∏j=1

bj

× srF

ks

[(a1 + s

k ; s, k), (a2 + sk ; s, k), · · · , (ar + s

k ; s, k)(b1 + s

k ; s, k), (b2 + sk ; s, k), · · · , (bq + s

k ; s, k)

∣∣∣∣z] .Proof. Consider

d

dzsrF

kq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣z]

=

r∏m=1

am

s∏j=1

bj

srF

ks

[(a1 + s

k ; s, k), (a2 + sk ; s, k), · · · , (ar + s

k ; s, k)(b1 + s

k ; s, k), (b2 + sk ; s, k), · · · , (bq + s

k ; s, k)

∣∣∣∣z] .

Lemma 3.16. Show that

dm

dzmsrF

kq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣z] =

r∏i=1

s(ai)kn

q∏j=1

s(bj)kn

× srF

kq

[(a1 + ms

k ; s, k), (a2 + msk ; s, k), · · · , (ar + ms

k ; s, k)(b1 + ms

k ; s, k), (b2 + msk ; s, k), · · · , (bq + ms

k ; s, k)

∣∣∣∣z] .Proof. Consider

dm

dzmsrF

kq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bs; s, k)

∣∣∣∣z]

=

r∏i=1

s(ai)km

q∏j=1

s(bj)km

srF

kq

[(a1 + ms

k ; s, k), (a2 + msk ; s, k), · · · , (ar + ms

k ; s, k)(b1 + ms

k ; s, k), (b2 + msk ; s, k), · · · , (bq + ms

k ; s, k)

∣∣∣∣z] .

Page 18: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 62

Theorem 3.17. Show that∞∫

0

e−pttkαs−1 s

r Fkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣xt] dt=kkαs−1 sΓk(α)

skαs−1p

kαs

sr+1F

kq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k), (α; s, k)

(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣kxsp],

where r ≤ q, <(p) > 0, <(α) > 0, s > k > 0.

Proof. Consider∞∫

0

e−pttkαs−1s

rFkq

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣xt] dt= s

r+1Fks

[(a1; s, k), (a2; s, k), · · · , (ar; s, k), (α; s, k)

(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣kxsp] ∞∫

0

e−pttkαs−1dt.

Since L{tn} = n!pn+1

F (s) =

∞∫0

e−ptf(t)dt.

So,∞∫

0

e−pttkαs−1 s

r Fks

[(a1; s, k), (a2; s, k), · · · , (ar; s, k)(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣xt] dt=kkαs−1 sΓk(α)

skαs−1p

kαs

sr+1F

ks

[(a1; s, k), (a2; s, k), · · · , (ar; s, k), (α; s, k)

(b1; s, k), (b2; s, k), · · · , (bq; s, k)

∣∣∣∣kxsp].

3.0.1. Saalschütz's (s, k)-theorem.

Theorem 3.18. If n is a non-negative integer and if a, b, c are independent of n, s > k > 0, then

s3F

k2

[(−nsk ; s, k), (a; s, k), (b; s, k)

(c; s, k), ( sk − c+ a+ b− nsk )

∣∣∣∣ks]

=s(c− b)kn s(c− a)kns(c)kn

s(c− a− b)kn.

Proof. Since theorem (3.6), we have

s2F

k1

[(c− a; s, k), (c− b; s, k)

(c; s, k)

∣∣∣∣z] = (1− (s/k)z)kc−ka−kb

ss2F

k1

[(a; s, k), (b; s, k)

(c; s, k)

∣∣∣∣z] .∞∑n=0

s(c− a)kns(c− b)kn zn

s(c)kn n!

=

∞∑n=0

∞∑m=0

s(a)kms(b)km

s(c− a− b)kn zm+n

s(c)km n!m!

=∞∑n=0

s(c− a− b)kn zn

n!s3F

k2

[(−nsk ; s, k), (a; s, k), (b; s, k)

(c; s, k), ( sk − c+ a+ b− nsk )

∣∣∣∣ks].

Page 19: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 63

Comparing coe�cient of zn

n! , we get

s3F

k2

[(−nsk ; s, k), (a; s, k), (b; s, k)

(c; s, k), ( sk − c+ a+ b− nsk )

∣∣∣∣ks]

=s(c− b)kn s(c− a)kns(c)kn

s(c− a− b)kn.

Theorem 3.19. If <(b) > <(a) > 0, s > k > 0, m ≥ 1, m ∈ Z+, then for all �nite z

smF

km

[(a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]

=k sΓk(b)

s sΓk(a) sΓk(b− a)

1∫0

tkas−1(1− t)

kb−kas−1ext

mdt.

Proof.

smF

km

[(a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]=

∞∑n=0

s( am)kns(ak+s

mk )kn · · · s(ak+(m−1)s

mk )kn zn

s( bm)kns( bk+s

mk )kn · · · s(bk+(m−1)s

mk )knn!.

Since s(b)knm = 2mn s( bm)kns( bk+s

mk )kn · · · s(bk+(m−1)s

mk )kn. Therefore

smF

km

[(a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]=

∞∑n=0

s(a)knm zn

s(b)knmn!.

By using s(a)knm =sΓk(a+(nms)/k)

sΓk(a), we have

smF

km

[(a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]=∞∑n=0

sΓk(a+ (nms)/k) sΓk(b) zn

sΓk(b+ (nms)/k) sΓk(a) n!

=k sΓk(b)

s sΓk(a) sΓk(b− a)

1∫0

tkas−1(1− t)

kb−kas−1ezt

mdt.

Theorem 3.20. If <(b) > <(a) > 0, s > k > 0, m ≥ 1, m ∈ Z+, then for all �nite z < ks

sm+1F

km

[(c; s, k), (a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)

(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]

=k sΓk(b)

s sΓk(a) sΓk(b− a)

1∫0

tkas−1(1− t)

kb−kas−1

(1− sxtm

k

)− kcs

dt.

Page 20: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 64

Proof.

sm+1F

km

[(c; s, k), (a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)

(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]=

∞∑n=0

s(c)kns( am)kn

s(ak+smk )kn · · · s(

ak+(m−1)smk )kn z

n

s( bm)kns( bk+s

mk )kn · · · s(bk+(m−1)s

mk )knn!.

Since s(b)knm = 2mn s( bm)kns( bk+s

mk )kn · · · s(bk+(m−1)s

mk )kn

sm+1F

km

[(c; s, k), (a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)

(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]=∞∑n=0

s(c)kns(a)knm zn

s(b)knmn!.

By using s(a)knm =sΓk(a+(nms)/k)

sΓk(a), we have

sm+1F

km

[(c; s, k), (a/m; s, k), ((a+ (s/k))/m; s, k), · · · , ((a+ ((m− 1)s/k))/m; s, k)

(b/m; s, k), ((b+ (s/k))/m; s, k), · · · , ((b+ ((m− 1)s/k))/m; s, k)

∣∣∣∣z]=∞∑n=0

s(c)knsΓk(a+ (nms)/k) sΓk(b) zn

sΓk(b+ (nms)/k) sΓk(a) n!

=k sΓk(b)

s sΓk(a) sΓk(b− a)

1∫0

tkas−1(1− t)

kb−kas−1

(1− sxtm

k

)− kcs

dt.

4. Conclusions

In this paper, we have de�ned the certain generalized special functions in terms of a new symbol (s, k),where s, k > 0 and called them special (s, k)-functions. We developed di�erential equation for hypergeometric(s, k)-functions in the form of (s, k) and their integral representations. Furthermore, we have obtained someuseful results and properties related to these special (s, k)-functions. If we take s = 1, then the obtainedresults are reduced to the special k-functions cited in literature. Similarly if we letting k = 1 in all de�nitionsand results, then certain new results in term of s can be obtained. If we letting both s = k = 1, then all theresults will reduce to the classical results.

References

[1] S. Araci, G. Rahman, A. Gha�ar, K.S. Nisar, Fractional calculus of extended Mittag-Le�er function and its applicationsto statistical distribution, Math., 7(3) (2019), 248.

[2] M.A. Chaudhry, S.M. Zubair, Generalized incomplete gamma functions with applications, J. Comp. Appl. Math., 55(1)(1994), 99-123.

[3] M.A. Chaudhry, S.M. Zubair, On the decomposition of generalized incomplete gamma functions with applications toFourier transforms, J. Comp. Appl. Math., 59(3) (1995), 253-284.

[4] M.A. Chaudhry, S.M. Zubair, Extended incomplete gamma functions with applications, J. Math. Anal. Appl., 274(2)(2002), 725-745.

[5] P. Agarwal, Q. Al-Mdallal, Y.J. Cho, S. Jain, Fractional di�erential equations for the generalized Mittag-Le�er function.Adv. Di�. Eq. (2018)(1), 1-8.

[6] Q. Al-Mdallal, M. Al-Refai, M. Syam, M.D.K. Al-Srihin, Theoretical and computational perspectives on the eigenvaluesof fourth-order fractional Sturm-Liouville problem, Int. J. Comp. Math., 95(8) (2018), 1548-1564.

[7] A. Babakhani, Q. Al-Mdallal, On the existence of positive solutions for a non-autonomous fractional di�erential equationwith integral boundary conditions, Comp. Meth. Di�. Eq., 9(1) (2021), 36-51.

Page 21: Some Generalized Special Functions and their Properties

Shahid Mubeen, et al., Adv. Theory Nonlinear Anal. Appl. 1 (2022), 45�65. 65

[8] F. Jarad, T. Abdeljawad, A modi�ed Laplace transform for certain generalized fractional operators, Nonlin. Anal., 1(2)(2018), 88-98.

[9] R. Diaz, C. Teruel, (q, k)-Generalized gamma and beta functions, J. Nonlin. Math. Phy., 12(2005), 118-134.[10] R. Diaz, E. Pariguan, On hypergeometric functions and Pochhammer k-symbol, Divul. Math., 15(2007), 179-192.[11] R. Diaz, C. Ortiz, E. Pariguan, On the k-gamma q-distribution, Cent. Eur. J. Math., 8 (2010), 448-458.[12] Kokologiannaki, CG: Properties and inequalities of generalized k-gamma, beta and zeta functions, Int. J. Contemp. Math.

Sci., 5, 653-660 (2010).[13] V. Krasniqi, A limit for the k-gamma and k-beta function. Int. Math. Forum. 5 (2010), 1613-1617.[14] M. Mansour, Determining the k-generalized gamma function Γk(x) by functional equations. International Journal of Con-

temporary Mathematical Sciences. 4, 1037-1042 (2009).[15] F. Merovci, Power product inequalities for the Γk function. Int. J. of Math. Analysis., 4(2010), 1007-1012.[16] S. Mubeen, S. Iqbal, Gruss type integral inequalities for generalized Riemann-Liouville k-fractional integrals, J. Ineq. Appl.

109 (2016), pp.13. Available online at https://doi.org/10.1186/s13660-016-1052-x.[17] S. Mubeen, S. Iqbal, Z. Iqbal. On Östrowski type inequalities for generalized k-fractional integrals, J. Ineq. Spec. Funct.,

8 (2017), no. 3, 107-118.[18] P. Agarwal, M. Jleli, M. Tomar. Certain Hermite-Hadamard type inequalities via generalized k-fractional integrals, J. Ineq.

Appl., 2017(55), 10. Available online at https://doi.org/10.1186/s13660-017-1318-y.[19] C.-J. Huang, G. Rahman, K. S. Nisar, A. Gha�ar, and F. Qi, Some inequalities of the Hermite-Hadamard type for

k-fractional conformable integrals, Austral. J. Math. Anal. Appl., 16(1) (2019).[20] G. Rahman, K.S. Nisar, A. Gha�ar, F. Qi, Some inequalities of the Gruss type for conformable k-fractional integral

operators, RACSAM, (2020) 114: 9. https://doi.org/10.1007/s13398-019-00731-3.[21] G.Farid, G.M. Habullah, An extension of Hadamard fractional integral. Int. J. Math. Anal., 9(10), 471-482 (2015).[22] M. Tomar, S. Mubeen, J. Choi, Certain inequalities associated with Hadamard k-fractional integral operators, J. Ineq.

Appl., (2016) (234), (2016).[23] G. Farid, A.U. Rehman, M. Zahra, on Hadamard-type inequalities for k-fractional integrals, Kon. J. Math., 4(2), 79-86

(2016).[24] S. Iqbal, S. Mubeen, M. Tomar, On Hadamard k-fractional integrals, J. Fract. Cal. Appl., 9(2) (2018), 255-267.[25] S. Habib, S. Mubeen, M.N. Naeem, F. Qi, Generalized k-fractional conformable integrals and related inequalities, AIMS

Math., 4(3), 343-358.[26] M. Samraiz, E. Set, M. Hasnain, G. Rahman, On an extension of Hadamard fractional derivative, J. Ineq. Appl. (2019)

2019:263. https://doi.org/10.1186/s13660-019-2218-0[27] E. Set, M.A. Noor, M.U. Awan, A. G¨ozpinar, Generalized Hermite-Hadamard type inequalities involving fractional

integral operators, J. Inequal. Appl. (2017), 169, 10. Available online at https://doi.org/10.1186/s13660-017-1444-6.[28] K.S. Nisar, G. Rahman, J. Choi, Certain Gronwall type inequalities associated with riemann-liouville and hadamard

k-fractional derivatives and their applications, E. Asi. Math. J., 34 (2018), 249-263.[29] G. Rahman, S. Mubeen, K.S. Nisar, On generalized k-fractional derivative operator, AIMS Mathematics, 5(3), 2019,

1936-1945.[30] K. Jangid, S.D. Prohit, K.S. Nisar, T. Abdeljawad, Certain Generalized Fractional Integral Inequalities. Advances in the

Theory of Nonlinear Analysis and its Application, 4(4) (2020), 252-259.[31] F. Qi, G. Rahman, S.M. Hussain, Some inequalities of Chebysev Type for conformable k-Fractional integral operators,

Symmetry, 10 (2018), 614.[32] S. Mubeen, Solution of Some integral equations involving con�uent k-hypergeometric functions, Appl. Math. 4, 9-11 (2013).[33] S. Mubeen, G.M. Habibullah, An integral representation of some k-hypergeometric functions, Int. Math. Forum. J. Th.

Appl., vol.7, 1-4. 203-207, 2012.[34] S. Mubeen, Solution of some integral equations involving con�uent k-hypergeometric functions, Applied Mathematics, vol.

4, no. 7A, pp. 9-11, 2013.[35] S. Mubeen, A. Rehman, A Note on k-Gamma function and Pochhammer k-symbol, J. Inf. Math. Sci. 2014, 6, 93-107.[36] S. Mubeen, M. Naz, A. Rehman, G. Rahman, Solutions of k-hypergeometric di�erential equations, J. Appl. Math. 2014,

(2014), 1-13.[37] S. Li, Y. Dong, k-hypergeometric series solutions to One type of non-homogeneous k-hypergeometric equations, Symmetry

(2019), 11, 262; doi:10.3390/sym11020262[38] G. Rahman, M. Arshad, S. Mubeen, Some results on generalized hypergeometric k-functions, Bull. Math. Anal. Appl. 8(3)

(2016), 66-77.[39] S. Mubeen, C.G. Kokologiannaki, G. Rahman, M. Arshad, Z. Iqbal, Properties of generalized hypergeometric k-functions

via k-fractional calculus, Far East Journal of Applied Mathematics, 96(6) (2017), 351-372.[40] F. Qi, A. Wand Geometric interpretations and reversed versions of Young's integral inequality, Adv. Theory Nonlin. Analy.

Appl.. 5 (2021) No.1, 1-6.[41] N. Adjimi, M. Benbachir, Katugampola fractional di�erential equation with Erdelyi-Kober integral boundary conditions,

Adv. Theory of Nonlin. Anal. Appl., 5 (2021) No. 2, 215-228.