How to prove the product representation of **Baenes G-function**?

66 Views Asked by At

How to prove the formula of Barnes G-dunction $$G(z+1)=(2\pi)^{z/2}\text{exp}\left(-\frac{z(z+1)}{2}- \frac{\gamma z^{2}}{2}\right)\, \prod_{k=1}^{\infty}\left(1+\frac{z}{k}\right)^{k}\text{exp}\left(\frac{z^2}{2k}-z\right)$$

1

There are 1 best solutions below

0
On

It's hard to prove that the formula works, because the function is inherently defined by the formula.

All other relationships pertaining to the Barnes G-function are derived, coincide, or in agreement with this definition. At its heart there is no difference between $G(z+1)$ and the RHS of the product representation.

I suppose you could go backward from other relations to prove that the formula is consistent, but you can't prove it intrinsically- it is defined in this way.