When you have a graph like this one here: https://www.dropbox.com/s/tchpodpt2gp1huf/Bisimulation.jpg Of course you find bisimilar points/paths. There must be two points or path that have the "greatest" bisimilarity of all. Is this not correct ? And if you have that kind of bisimilarity, how do you find it among all the paths ? In other words, where is the pair that is more bisimilar than all the others?