\begin{figure}[htb]\caption{and-parallelism} \setlength{\unitlength}{0.01cm} \nop{ ) } \hspace{1.7cm} \begin{tabular}[t]{|p{ 4.0cm}|p{ 4.0cm}|p{ 4.0cm}|} \hline \multicolumn{3}{|c|}{ \it And-parallel goal evaluation } \\ \hline \hline \begin{picture}(400,275)(0,0) \put(125,200){\makebox(0,0)[r]{ A&B } } \put(125,150){\makebox(0,0)[r]{ B } } \put(250,200){\makebox(0,0)[l]{ A } } \put(125,150){\circle{10}} \put(125,200){\circle{10}} \put(250,200){\circle*{10}} \put(125, 210){\line(0,6){ 50}} \put(125, 160){\line(0,6){ 30}} \multiput( 135,200)(10,0){ 12}{\line(6,0){5}} \end{picture} & \begin{picture}(400,275)(0,0) \put(125,200){\makebox(0,0)[r]{ A&B } } \put(125,150){\makebox(0,0)[r]{ B } } \put(125,75){\makebox(0,0)[r]{ Q? } } \put(250,200){\makebox(0,0)[l]{ A } } \put(125,75){\circle{10}} \put(125,150){\circle{10}} \put(125,200){\circle{10}} \put(250,200){\circle*{10}} \put(125, 210){\line(0,6){ 50}} \put(125, 85){\line(0,6){ 55}} \put(125, 160){\line(0,6){ 30}} \multiput(250, 85)(0, 20){ 6}{\line(0,6){10}} \multiput( 135,200)(10,0){ 12}{\line(6,0){5}} \end{picture} & \begin{picture}(400,275)(0,0) \put(125,200){\makebox(0,0)[r]{ A&B } } \put(125,150){\makebox(0,0)[r]{ B } } \put(125,75){\makebox(0,0)[r]{ Q? } } \put(250,75){\makebox(0,0)[l]{ %h_1,%h_2,... } } \put(250,200){\makebox(0,0)[l]{ A } } \put(125,75){\circle{10}} \put(125,150){\circle{10}} \put(125,200){\circle{10}} \put(250,75){\circle{10}} \put(250,200){\circle*{10}} \put(125, 210){\line(0,6){ 50}} \put(125, 65){\line(0,-6){25}} \put(125, 85){\line(0,6){ 55}} \put(125, 160){\line(0,6){ 30}} \multiput(250, 85)(0, 20){ 6}{\line(0,6){10}} \multiput( 135,75)(10,0){ 12}{\line(6,0){5}} \put( 145,75){\vector(-4,0){ 20}} \multiput( 135,200)(10,0){ 12}{\line(6,0){5}} \end{picture} \\ \hline \hline \leftcomment{goal} A&B & B & Q? \\ \leftcomment{effect} \small \sloppy A new process is created, \n to evaluate the method call A. & \small \sloppy During the remote evaluation of A the goal B is evaluated by the process itself. & \small \sloppy The results of evaluating B and A are merged. Backtracking over the solutions for A may occur. \\ \hline \nop{ \it definition & \multicolumn{3}{|l|}{\x A & B :- Q = self!A, B, Q? } \\ \hline } \end{tabular} \end{figure}