The Gaussian q-density.
Let q be a real number in the interval [0, 1). The probability density function of the Gaussian q -distribution is given by
s
q
(
x
)
=
{
0
if
x
<
−
ν
1
c
(
q
)
E
q
2
−
q
2
x
2
[
2
]
q
if
−
ν
≤
x
≤
ν
0
if
x
>
ν
.
{\displaystyle s_{q}(x)={\begin{cases}0&{\text{if }}x<-\nu \\{\frac {1}{c(q)}}E_{q^{2}}^{\frac {-q^{2}x^{2}}{[2]_{q}}}&{\text{if }}-\nu \leq x\leq \nu \\0&{\mbox{if }}x>\nu .\end{cases}}}
where
ν
=
ν
(
q
)
=
1
1
−
q
,
{\displaystyle \nu =\nu (q)={\frac {1}{\sqrt {1-q}}},}
c
(
q
)
=
2
(
1
−
q
)
1
/
2
∑
m
=
0
∞
(
−
1
)
m
q
m
(
m
+
1
)
(
1
−
q
2
m
+
1
)
(
1
−
q
2
)
q
2
m
.
{\displaystyle c(q)=2(1-q)^{1/2}\sum _{m=0}^{\infty }{\frac {(-1)^{m}q^{m(m+1)}}{(1-q^{2m+1})(1-q^{2})_{q^{2}}^{m}}}.}
The q -analogue [t ]q of the real number
t
{\displaystyle t}
is given by
[
t
]
q
=
q
t
−
1
q
−
1
.
{\displaystyle [t]_{q}={\frac {q^{t}-1}{q-1}}.}
The q -analogue of the exponential function is the q-exponential , E x q , which is given by
E
q
x
=
∑
j
=
0
∞
q
j
(
j
−
1
)
/
2
x
j
[
j
]
!
{\displaystyle E_{q}^{x}=\sum _{j=0}^{\infty }q^{j(j-1)/2}{\frac {x^{j}}{[j]!}}}
where the q -analogue of the factorial is the q-factorial , [n ]q !, which is in turn given by
[
n
]
q
!
=
[
n
]
q
[
n
−
1
]
q
⋯
[
2
]
q
{\displaystyle [n]_{q}!=[n]_{q}[n-1]_{q}\cdots [2]_{q}\,}
for an integer n > 2 and [1]q ! = [0]q ! = 1.
The Cumulative Gaussian q-distribution.
The cumulative distribution function of the Gaussian q -distribution is given by
G
q
(
x
)
=
{
0
if
x
<
−
ν
1
c
(
q
)
∫
−
ν
x
E
q
2
−
q
2
t
2
/
[
2
]
d
q
t
if
−
ν
≤
x
≤
ν
1
if
x
>
ν
{\displaystyle G_{q}(x)={\begin{cases}0&{\text{if }}x<-\nu \\[12pt]\displaystyle {\frac {1}{c(q)}}\int _{-\nu }^{x}E_{q^{2}}^{-q^{2}t^{2}/[2]}\,d_{q}t&{\text{if }}-\nu \leq x\leq \nu \\[12pt]1&{\text{if }}x>\nu \end{cases}}}
where the integration symbol denotes the Jackson integral .
The function G q is given explicitly by
G
q
(
x
)
=
{
0
if
x
<
−
ν
,
1
2
+
1
−
q
c
(
q
)
∑
n
=
0
∞
q
n
(
n
+
1
)
(
q
−
1
)
n
(
1
−
q
2
n
+
1
)
(
1
−
q
2
)
q
2
n
x
2
n
+
1
if
−
ν
≤
x
≤
ν
1
if
x
>
ν
{\displaystyle G_{q}(x)={\begin{cases}0&{\text{if }}x<-\nu ,\\\displaystyle {\frac {1}{2}}+{\frac {1-q}{c(q)}}\sum _{n=0}^{\infty }{\frac {q^{n(n+1)}(q-1)^{n}}{(1-q^{2n+1})(1-q^{2})_{q^{2}}^{n}}}x^{2n+1}&{\text{if }}-\nu \leq x\leq \nu \\1&{\text{if}}\ x>\nu \end{cases}}}
where
(
a
+
b
)
q
n
=
∏
i
=
0
n
−
1
(
a
+
q
i
b
)
.
{\displaystyle (a+b)_{q}^{n}=\prod _{i=0}^{n-1}(a+q^{i}b).}