WHAT IS GAMMA FUNCTION AND HOW IT IS USEFUL IN PHYSICS?

The gamma function is an extension of factorial function.

If n is a positive integer :

The gamma function is defined for all complex numbers except the negativeintegers and zero. For complex numbers with a positive real part, it is defined via a convergent improper integral :

In particular, the incomplete gamma function is used in solid state physics and statistics, and the logarithm of the gamma function is used in discrete mathematics, number theory, and other fields of sciences.
Thanks & Regards

Bharat Bajaj
askiitian faculty
IIT Delhi