I'm wondering how the Rabin kindness function for player 1 is composed in [1]. Specifically: How is the equitable payoff calculated with [1]? The correct equitable payoff should be 6X if f1(Trust, Share) and 8.5X if f1(Trust, Grab).
Equitable payoff definition: Player 2's highest payoff in PI(bj) and the lowest payoff of player j among points that are pareto-efficient in PI(bj).
I think there are only 2 really pareto-efficient payoffs: Trust/Share and Trust/Grab. To calculate the equitable payoff I would then use (6X+6X)/2 for Share and (12X+12X)/2 for Grab (as there are for both cases each only 1 pareto-efficient outcomes). Perhaps the term pareto efficient is not strictly meant here (because it doesn't lay on the production possibility frontier) and also includes 5X;5X on Grab because Player 2 cannot be better off without taking something from Player 1 away.
Payoff table: https://i.stack.imgur.com/mIzu7.png
