good way to satisfy such queries for examplecalling successors(kon query key (ordpvd may : )could result in an iterator with the following entries((ordpvd may : )(aa : $ )((ordpvd may : )(aa : $ )((ordpvd may : )(aa : $ )((ordpvd may : )(aa : $ )maxima sets life is full of trade-offs we often have to trade off desired performance measure against corresponding cost supposefor the sake of an examplewe are interested in maintaining database rating automobiles by their maximum speeds and their cost we would like to allow someone with certain amount to spend to query our database to find the fastest car they can possibly afford we can model such trade-off problem as this by using key-value pair to model the two parameters that we are trading offwhich in this case would be the pair (costspeedfor each car notice that some cars are strictly better than other cars using this measure for examplea car with cost-speed pair ( , , is strictly better than car with cost-speed pair ( , , at the same timethere are some cars that are not strictly dominated by another car for examplea car with cost-speed pair ( , may be better or worse than car with costspeed pair ( , )depending on how much money we have to spend (see figure figure illustrating the cost-performance tradeoff with key-value pairs represented by points in the plane notice that point is strictly better than points cdand ebut may be better or worse than points abfgand hdepending on the price we are willing to pay thusif we were to add to our setwe could remove the points cdand ebut not the others