+\begin{table}
+ \caption{\label{tab:il2f1} Instantiation of level 2 patterns from level 1.
+ \strut}
+\hrule
+\[
+\begin{array}{rcll}
+
+\IOT{C[t_1,\dots,t_n]}{\mathcal{E}} & =
+& C[\IOT{t_1}{\mathcal{E}},\dots,\IOT{t_n}{\mathcal{E}}] \\
+
+\IOT{\mathtt{term}~x}{\mathcal{E}} & = & t & \mathcal{E}(x) = \mathtt{Term}~t \\
+
+\IOT{\mathtt{number}~x}{\mathcal{E}} & =
+& n & \mathcal{E}(x) = \mathtt{Number}~n \\
+
+\IOT{\mathtt{ident}~x}{\mathcal{E}} & =
+& y & \mathcal{E}(x) = \mathtt{String}~y \\
+
+\IOT{\mathtt{fresh}~x}{\mathcal{E}} & = & y & \mathcal{E}(x) = \mathtt{String}~y \\
+
+\IOT{\mathtt{default}~P_1~P_2}{\mathcal{E}} & =
+& \IOT{P_1}{\UPDATE{\mathcal{E}}{x_i|->v_i}}
+& \mathcal{E}(x_i)=\mathtt{Some}~v_i \\
+& & & \NAMES(P_1)\setminus\NAMES(P_2)=\{x_1,\dots,x_n\} \\
+
+\IOT{\mathtt{default}~P_1~P_2}{\mathcal{E}} & =
+& \IOT{P_2}{\UPDATE{\mathcal{E}}{x_i|->\bot}}
+& \mathcal{E}(x_i)=\mathtt{None} \\
+& & & \NAMES(P_1)\setminus\NAMES(P_2)=\{x_1,\dots,x_n\} \\
+
+\IOT{\mathtt{fold}~\mathtt{right}~P_1~\mathtt{rec}~x~P_2}{\mathcal{E}}
+& =
+& \IOT{P_1}{\mathcal{E}'}
+& \mathcal{E}(\NAMES(P_2)\setminus\{x\}) = \{[],\dots,[]\} \\
+& & \multicolumn{2}{l}{\mathcal{E}'=\UPDATE{\mathcal{E}}{\NAMES(P_2)\setminus\{x\}|->\bot}}
+\\
+
+\IOT{\mathtt{fold}~\mathtt{right}~P_1~\mathtt{rec}~x~P_2}{\mathcal{E}}
+& =
+& \IOT{P_2}{\mathcal{E}'}
+& \mathcal{E}(y_i) = [v_{i1},\dots,v_{in}] \\
+& & & \NAMES(P_2)\setminus\{x\}=\{y_1,\dots,y_m\} \\
+& & \multicolumn{2}{l}{\mathcal{E}'(y) =
+ \left\{
+ \begin{array}{@{}ll}
+ \IOT{\mathtt{fold}~\mathtt{right}~P_1~\mathtt{rec}~x~P_e}{\mathcal{E}''}
+ & y=x \\
+ v_{i1} & y=y_i \\
+ \mathcal{E}(y) & \mbox{otherwise} \\
+ \end{array}
+ \right.} \\
+& & \multicolumn{2}{l}{\mathcal{E}''(y) =
+ \left\{
+ \begin{array}{@{}ll}
+ [v_{i2};\dots;v_{in}] & y=y_i \\
+ \mathcal{E}(y) & \mbox{otherwise} \\
+ \end{array}
+ \right.} \\
+
+\IOT{\mathtt{fold}~\mathtt{left}~P_1~\mathtt{rec}~x~P_2}{\mathcal{E}}
+& =
+& \mathit{eval\_fold}(x,P_2,\mathcal{E}')
+& \\
+& & \multicolumn{2}{l}{\mathcal{E}' = \UPDATE{\mathcal{E}}{x|->
+\IOT{P_1}{\UPDATE{\mathcal{E}}{\NAMES(P_2)|->\bot}}}} \\
+
+\mathit{eval\_fold}(x,P,\mathcal{E})
+& =
+& \mathcal{E}(x)
+& \mathcal{E}(\NAMES(P)\setminus\{x\})=\{[],\dots,[]\} \\
+
+\mathit{eval\_fold}(x,P,\mathcal{E})
+& =
+& \mathit{eval\_fold}(x,P,\mathcal{E}')
+& \mathcal{E}(y_i) = [v_{i1},\dots,v_{in}] \\
+& & & \NAMES(P)\setminus{x}=\{y_1,\dots,y_m\} \\
+&
+& \multicolumn{2}{l}{\mathcal{E}' = \UPDATE{\mathcal{E}}{x|->\IOT{P}{\mathcal{E}''}; ~ y_i |-> [v_{i2};\dots;v_{in_i}]}}
+\\
+&
+& \multicolumn{2}{l}{\mathcal{E}''(y) =
+\left\{
+\begin{array}{ll}
+ v_1 & y\in \NAMES(P)\setminus\{x\} \\
+ \mathcal{E}(x) & y=x \\
+ \bot & \mathit{otherwise} \\
+\end{array}
+\right.
+}
+\\
+
+\end{array} \\
+\]
+\end{table}
+