Thomae's Transformation

Theorem
Let $a, b, c, e, f, s \in \C$.

Let $s = e + f - a - b - c$

Then:
 * $\ds \map { {}_3 \operatorname F_2} { { {a, b, c} \atop {e, f} } \, \middle \vert \, 1} = \dfrac {\map \Gamma e \map \Gamma f \map \Gamma s } {\map \Gamma a \map \Gamma {s + b} \map \Gamma {s + c} } \map { {}_3 \operatorname F_2} { { {e - a, f - a, s} \atop {s + b, s + c} } \, \middle \vert \, 1} $

where:
 * $\ds \map { {}_3 \operatorname F_2} { { {a, b, c} \atop {e, f} } \, \middle \vert \, 1}$ is the generalized hypergeometric function of $1$: $\ds \sum_{k \mathop = 0}^\infty \dfrac { a^{\overline k} b^{\overline k} c^{\overline k} } { e^{\overline k} f^{\overline k} } \dfrac {1^k} {k!}$
 * $x^{\overline k}$ denotes the $k$th rising factorial power of $x$
 * $\map \Gamma {n + 1} = n!$ is the Gamma function.

Proof
First, we observe that:

We now have:

Also known as

 * Thomae's Transformation is also known as Thomae's Theorem.

Also see

 * Euler's Transformation
 * Kummer's Quadratic Transformation
 * Pfaff's Transformation