Connections within the group of gamma functions and with other
function groups Representations through more general functions
The gamma function is the main example of a group of functions
collectively referred to as gamma functions. For example, it can
be written in terms of the incomplete gamma function: All four
incomplete gamma functions , , , and can be represented as cases
of the hypergeometric function . Further, the gamma function
Γ(z) is the special degenerate case of the hypergeometric
function . Representations through related equivalent functions
The gamma function and two factorial functions are connected by
the formulas: