3.I.8B

Further Complex Methods
Part II, 2007

Let w1(z)w_{1}(z) and w2(z)w_{2}(z) be any two linearly independent branches of the PP-function

{01αβγzαβγ}\left\{\begin{array}{cccc} 0 & \infty & 1 & \\ \alpha & \beta & \gamma & z \\ \alpha^{\prime} & \beta^{\prime} & \gamma^{\prime} & \end{array}\right\}

where α+α+β+β+γ+γ=1\alpha+\alpha^{\prime}+\beta+\beta^{\prime}+\gamma+\gamma^{\prime}=1, and let W(z)W(z) be the Wronskian of w1(z)w_{1}(z) and w2(z)w_{2}(z).

(i) How is W(z)W(z) related to the Wronskian of the principal branches of the PP-function at z=0z=0 ?

(ii) Show that zαα+1(1z)γγ+1W(z)z^{-\alpha-\alpha^{\prime}+1}(1-z)^{-\gamma-\gamma^{\prime}+1} W(z) is an entire function.

(iii) Given that zβ+β+1W(z)z^{\beta+\beta^{\prime}+1} W(z) is bounded as zz \rightarrow \infty, show that

W(z)=Azα+α1(1z)γ+γ1W(z)=A z^{\alpha+\alpha^{\prime}-1}(1-z)^{\gamma+\gamma^{\prime}-1}

where AA is a non-zero constant.