\begin{tabular}{| l |c |c |c |c |c |}
\hline \multicolumn{2}{|c|}{Proof obligations } & \provername{Alt-Ergo (0.94)} & \provername{Coq (8.3pl4)} & \provername{Simplify (1.5.4)} \\ 
\hline 
\explanation{G1} & & \noresult& \noresult& \valid{0.00} \\ 
\hline 
\explanation{G2} & & \unknown{0.00} & \noresult& \unknown{0.00} \\ 
\cline{2-4} 
 & \explanation{1.} & \unknown{0.00} & \unknown{0.43} & \unknown{0.00} \\ 
\cline{2-5} 
 & \explanation{2.} & \valid{0.00} & \noresult& \valid{0.00} \\ 
\hline 
\explanation{G3} & & \valid{0.00} & \noresult& \unknown{0.00} \\ 
\hline \end{tabular}
