fix: Error in Backtrack recurse of a single alignment

content/chapters/part2/1.tex

@@ -167,7 +167,7 @@
 		\State $z = \begin{pmatrix} S_{1}[i-1] \\ \varepsilon \end{pmatrix} \circ z$
 		\ElsIf {$j > 0$}
 		\State $z = $ \Call{BacktrackRecurse}{$S_{1}$, $S_{2}$, $M$, $i$, $j-1$}
-		\State $z = \begin{pmatrix} S_{1}[i-1] \\ \varepsilon \end{pmatrix} \circ z$
+		\State $z = \begin{pmatrix} \varepsilon \\ S_{2}[j-1] \end{pmatrix} \circ z$
 		\Else
 		\State \Return []
 		\EndIf