to the person who asked, I am not a lawyer, therefore cannot dispense legal advice. I am a mediator and can facilitate meetings with the goal of having disputing parties reach a mutual agreement. BATNa is best alternative negotiated where both parties try to reach a mutual agreement on the outcome. Arbitration is where I propose alternatives.
BATNA was developed by negotiation researchers Roger Fisher and William Ury of the Harvard Program on Negotiation (PON), in their series of books on Principled negotiation that started with Getting to YES, unwittingly duplicating a game theory concept pioneered by Nobel Laureate John Forbes Nash decades earlier in his early undergraduate research. Equilibrium theory explains that, if in a group of players, each player has in consideration the other player’s decisions, then no one will benefit from altering their decisions, if the other players haven’t either. For example, Amy and Phil are in Nash Equilibrium if Amy is making the best decision she can, taking into account Phil’s decision, and Phil is making the best decision he can, taking into account Amy’s decision. Likewise, a group of players are in Nash Equilibrium if each one is making the best decision that he or she can, taking into account the decisions of the others.
A ruthless, aggressive and cold blooded negotiation style is the framework approach most people have when it comes to negotiation, a theoretical example of that is Adversarial Approach Style Negotiation. But in reality, as mentioned by experts and researchers such as Fisher and Ury  it doesn’t have to be that way. As the world moves to more sophisticated platforms of communication, negotiation follows the trend and Problem-Solving Approach is in a way, the “antidote” of Adversarial Approach Style Negotiation.