content_image/319320.jpg content_image/319321.jpg content_image/319322.jpg content_image/319323.jpg content_image/319324.jpg
We note that 

<img src='content_image/319320.jpg'>

since z = 0 on Γ$_{x}$ ∪ Γ$_{y}$. We multiply (3.30) by − sγ (4 α + µ ), then we have 

<img src='content_image/319321.jpg'>

where we choose µ > 0 later and 

By adding (3.29) and (3.31) we have 

<img src='content_image/319322.jpg'>

<img src='content_image/319323.jpg'>

<img src='content_image/319324.jpg'>

