-Let $y=(e,((u^0, \dots, u^{\sum_{l=0}^{k_1}v^l-1}, a_0^0, \dots, a_0^{|a_0|}, a_1^0, \dots, $ \linebreak
-$a_1^{|a_1|},\dots, a_{k_2}^0, \dots, a_{k_2}^{|a_{k_2}|},$
- $\check{u}^0, \check{u}^1, \dots),(v^0, \dots, v^{k_1},|a_0|, \dots,$\linebreak
- $|a_{k_2}|,\check{v}^0, \check{v}^1, \dots)))$. So $y\in \mathcal{B}(x,\varepsilon)$
+Let
+
+\begin{eqnarray*}
+y&=&(e,(
+(u^0, \dots, u^{\sum_{l=0}^{k_1}v^l-1}, a_0^0, \dots, a_0^{|a_0|}, a_1^0, \dots,
+a_1^{|a_1|},\dots, a_{k_2}^0, \dots, a_{k_2}^{|a_{k_2}|},
+ \check{u}^0, \check{u}^1, \dots), \\
+&&\qquad(v^0, \dots, v^{k_1},|a_0|, \dots,
+ |a_{k_2}|,\check{v}^0, \check{v}^1, \dots))).
+\end{eqnarray*}
+So $y\in \mathcal{B}(x,\varepsilon)$