ABSTRACT

Chapter 1

DEFINITION, REPRESENTATIONS AND

EXPANSIONS OF THEH-FUNCTION

1.1. Denition of the H-Function

For integersm;n; p; q such that 0 5 m 5 q; 0 5 n 5 p; for a

i

; b

j

2 C with C ; the set of complex

numbers, and for

i

;

j

2 R

+

= (0;1) (i = 1; 2; ; p; j = 1; 2; ; q); theH-functionH

m;n

p;q

(z)

is dened via a Mellin{Barnes type integral in the form

H

m;n

p;q

(z) H

m;n

p;q

"

z

(a

i

;

i

)

1;p

(b

j

;

j

)

1;q

#

H

m;n

p;q

"

z

(a

p

;

p

)

(b

q

;

q

)

#

H

m;n

p;q

"

z

(a

;

); ; (a

p

;

p

)

(b

;

); ; (b

q

;

q

)

#

=

2i

Z

L

H

m;n

p;q

(s)z

s

ds (1.1.1)

with

H

m;n

p;q

(s) H

m;n

p;q

"

(a

i

;

i

)

1;p

(b

j

;

j

)

1;q

s

#

H

m;n

p;q

"

(a

p

;

p

)

(b

q

;

q

)

s

#

=

m

Y

j=1

(b

j

+

j

s)

n

Y

i=1

(1 a

i

i

s)

p

Y

i=n+1

(a

i

+

i

s)

q

Y

j=m+1

(1 b

j

j

s)

: (1.1.2)

Here

z

s

= exp[sflog jzj+ i arg zg]; z 6= 0; i =

p

1; (1.1.3)

where log jzj represents the natural logarithm of jzj and arg z is not necessarily the principal

value. An empty product in (1.1.2), if it occurs, is taken to be one, and the poles

b

jl

=

b

j

l

j

(j = 1; ; m; l = 0; 1; 2; ) (1.1.4)

of the gamma functions (b

j

+

j

s) and the poles

a

ik

=

1 a

i

+ k

(i = 1; ; n; k = 0; 1; 2; ) (1.1.5)

i

i

i

(b

j

+ l) 6=

j

(a

i

k 1) (i = 1; ; n; j = 1; ; m; k; l = 0; 1; 2; ): (1.1.6)

L in (1.1.1) is the innite contour which separates all the poles b

jl

in (1.1.4) to the left and

all the poles a

ik

in (1.1.5) to the right of L; and has one of the following forms:

(i) L = L

is a left loop situated in a horizontal strip starting at the point 1 + i'

and terminating at the point 1+ i'

with 1 < '

< '

< +1;

(ii) L = L

+1

is a right loop situated in a horizontal strip starting at the point +1+ i'

and terminating at the point +1+ i'

with 1 < '

< '

< +1:

(iii) L = L

i 1

is a contour starting at the point i1 and terminating at the point

+ i1; where 2 R= (1;+1).