Initial update commit.

document.tex

@@ -18,6 +18,8 @@
 
 \numberwithin{equation}{subsection}
 
+\newcommand{\hi}{gamer}
+
 \begin{document}
 
 \chapter{A first chapter}
@@ -28,8 +30,13 @@
 
 \begin{lemma}
   \label{lemma:pythagoras}
-  $a^2=b^2+c^2$
+  $a^2=b^2+c^2 \hello$
+\hi
 \end{lemma}
+\begin{proof}
+hihihihihihihi
+\[\xymatrix{ &  Y_1 &  \\  X \ar[ru]^{f_1} \ar[r]^{f_3} \ar[rd]_{f_2} &  Y_3 \ar[u]_{a_{31}} \ar[d]^{a_{32}} &  Y \ar[lu]_{s_1} \ar[l]_{s_3} \ar[ld]^{s_2} \\  &  Y_2 &  }\]
+\end{proof}
 
 \section{A second section}
 \label{section:second}