 e_{|{\partial}\Pi |} h_{|{\partial}\Pi |}$, where $h_i$ is a closed subpath of ${\partial}{\Delta}$, then, for every $i$, $h_i$ is a subpath of either ${\alpha}( p_0)$ or ${\alpha}( p_0) {\alpha}( p_0)$ and $|h_i | \le \tfrac 00 |W|$