Improve formulation definition in schemes

Thanks to Harry
http://stacks.math.columbia.edu/tag/01J4#comment-2616

schemes.tex

@@ -2094,9 +2094,9 @@ \section{Reduced schemes}
 
 \begin{definition}
 \label{definition-reduced-induced-scheme}
-Let $X$ be a scheme. Let $i : Z \to X$ be the inclusion of a closed subset.
+Let $X$ be a scheme. Let $Z \subset X$ be a closed subset.
 A {\it scheme structure on $Z$} is given by a closed subscheme $Z'$ of
-$X$ whose underlying closed is equal to $Z$. We often say
+$X$ whose underlying set is equal to $Z$. We often say
 ``let $(Z, \mathcal{O}_Z)$ be a scheme structure on $Z$'' to
 indicate this. The {\it reduced induced scheme structure}
 on $Z$ is the one constructed in Lemma \ref{lemma-reduced-closed-subscheme}.