 Incomplete gamma function

The upper incomplete gamma function is $\gamma (x,y)={\int }_y^{\infty }{t}^{x-1}{e}^{-t}dt$ under the convention used here.

The incomplete gamma function is a mathematical function that generalizes the gamma function, which itself is a fundamental function in mathematics, particularly in the fields of statistics and probability theory. The incomplete gamma function is useful in various applications, including statistical distributions and hypothesis testing. The incomplete gamma function is defined in two forms: the lower incomplete gamma function and the upper incomplete gamma function.