First study what is the extended game, and then verify whether the open patent only involves other things.

Extended game is an extended form, which is an expression to describe the game through trees. Then, it is verified that public patents are not only related to others. Each node of the extended game (called decision node) represents every possible state in the game. The game starts from the only initial node and reaches the end node through the path determined by the participants. At this point, the game is over and the participants get the corresponding benefits. Each non-terminal node belongs to only one participant. Participants choose their possible actions at this node, and each possible action reaches another node from this node through an edge. Different from the conventional form, the extended form allows an explicit interaction model, in which a participant can act many times in the game and make different behaviors in different States.