From Wikipedia,
The upper incomplete gamma function defined as:
$$\Gamma(s,x) = \int_{x}^{\infty}t^{s-1}e^{-t}dt$$
whereas the lower incomplete gamma function is defined as
$$\gamma(s,x) = \int_{0}^{x}t^{s-1}e^{-t}dt.$$
My question is that can we write the following equation. How can we write or is there any reference
$$\gamma(s + 1,x) = \int_{0}^{x}t^{s}e^{-t}dt.$$
Thanks in advance: