figure two searches that arrive at identical position tree is actually constructed by the algorithm the game tree is just an abstract concept the value of the game tree is figure shows the evaluation of the same game tree with several (but not all possibleunevaluated nodes almost half of the terminal nodes have not been checked we show that evaluating them would not change the value at the root firstconsider node figure shows the information that has been gathered when it is time to evaluate at this pointwe are still in findhumanmove and are contemplating call to findcompmove on howeverwe already know that findhumanmove will return at most since it is min node on the other handits max node parent has already found sequence that guarantees nothing that does can possibly increase this value therefored does not need to be evaluated this pruning of the tree is known as pruning an identical situation occurs at node to implement pruningfindcompmove passes its tentative maximum (ato findhumanmove if the tentative minimum of findhumanmove falls below this valuethen findhumanmove returns immediately similar thing happens at nodes and this timewe are in the middle of findcompmove and are about to make call to findhumanmove to evaluate figure shows the situation that is encountered at node howeverthe findhumanmoveat the min max min figure hypothetical game tree max min max