Digital Library of Mathematical Functions
The Gamma Function -- Notation

Notation

j , m , n nonnegative integers.
k except in Physical Applications
x , y real variables.
z = x + y complex variable.
a , b , q , s , w real or complex variables with q < 1 .
δ arbitrary small positive constant.
complex plane (excluding infinity).
real line (excluding infinity).
( n m ) binomial coefficient n ! m ! ( n - m ) ! .
empty sums zero.
empty products unity.

The main functions treated in this chapter are the gamma function Γ ( z ) ,the psi function ψ ( z ) ,the beta function B ( a , b ) , and the q -gamma function Γ q ( z ) .

The notation Γ ( z ) is due to Legendre. Alternative notations for this function are: Π ( z - 1 ) (Gauss) and ( z - 1 ) ! . Alternative notations for the psi function are: