\begin{frame} \frametitle{ILPO} \begin{claim} $\rewlex{\arel}$ is a reduction order, that is: \begin{itemize} \item $\rewlex{\arel}$ is well-founded, and \item closed under substitution and contexts \end{itemize} \end{claim} \pause \medskip The closure under substitutions and contexts is immediate since ${\reltra{\airew{\itrslex{\arel}}}}$ is. \pause\medskip \alert{Only required}: proof of termination of $\rewlex{\arel}$. \medskip\pause \begin{corollary} A TRS $\atrs$ is terminating if ${\atrs} \subseteq {\rewlex{\arel}}$. \end{corollary} \smallskip \pause {\bf Proof.} $\rewlex{\arel}$ is a reduction order with ${\atrs} \subseteq {\rewlex{\arel}}$. \end{frame}