Remove badly parsed sentence

implementation.tex

@@ -52,7 +52,7 @@ We compute the affine representation of $x_R$ and $y_R$ by computing the inverse
 Like most implementations of Curve25519 scalar multiplication, 
 we use Fermat's little theorem and raise $Z_R$ to the power $2^{255} - 21$ to obtain $Z_R^{-1}$. 
 We chose not to exploit the optimization described in~\cite{BY19}, 
-because the implementations we compare to have not had the opportunity to implement this technique; 
+because previous implementations have not had the opportunity to implement this technique; 
 exploiting this invention would give us an unfair advantage.
 
 In the following subsections we describe the architecture-specific optimizations