\newcommand{\qed}{\square}
\newcommand{\proofstarts}{{\it Proof:}}
\newcommand{\proof}[1]{\proofstarts #1 $\qed$}
+\newcommand{\commitproof}[1]{{\it Proof of commit generation conditions:}
+ #1 $\qed$}
\newcommand{\statement}[2]{\[\eqn{ #1 }{ #2 }\]}